You'll need to provide more information, an extract of the cpan output where the failure is occurring would be a good start. Please read and understand How do I post a question effectively? and PerlMonks for the Absolute Beginner.

Check out this relevant link , the top reply also had a similar issue on Windows, and was able to fix it by modifying the config.

Here's another possible solution in a different thread involving an issue with date and time settings.

cpan -i Net::SFTP::Foreign::Backend::Net_SSH2
[download]

It would have been more helpful if you could have provided more text from the error message. When I tried installing Net::SFTP on a system using portable Strawberry Perl, my attempt failed at the same point as the post from Cow1337killr. In particular, I got something similar to this excerpt from Cow1337killr's post:

dmake.exe:  Error code 129, while making 'Curve25519.o'
  AJGB/Crypt-Curve25519-0.05.tar.gz
  C:\STRAWB~1\c\bin\dmake.exe -- NOT OK
Stopping: 'install' failed for 'Crypt::Curve25519'.
Failed during this command:
 AJGB/Crypt-Curve25519-0.05.tar.gz            : make NO
[download]

Doing a little checking on the Crypt::Curve25519 module (which appears to be the source of the issue), there doesn't seem to be any tests that passed in the mswin32 column of its CPAN Testers matrix. Also, it looks like someone has already filed a bug report on this issue - and for whatever reason, there doesn't seem to be a response yet from the module's author.

If you're not willing to wait for the module's author to fix this issue and are not interested in figuring out a patch for this issue yourself, then it looks like using Net::SFTP may not be an option. Of course, syphilis shared an alternative solution in his post.

dmake.exe: Error code 129, while making 'Curve25519.o'

The problem lies with the symbol "OUT".
Consider this C program:

#include <windows.h>

int main(void) {
 int OUT = 7;
 return 0;
}
[download]

If you attempt to compile that program on Windows, you get:

try.c: In function 'main':
try.c:4:10: error: expected identifier or '(' before '=' token
  int OUT = 7;
          ^
[download]

I think that's a pretty good indication that OUT is a special symbol on Windows.
The program builds fine if windows.h is not included but, of course, windows.h is included for the xs file.

Simplest solution would be to replace the symbol "OUT" with something that's not going to clash.
(I'll add that to the bug report unless someone else beats me to it.)

Cheers,
Rob

I was unable to install the module.

C:\path to my folder\Perl scripts>cpan
Loading internal null logger. Install Log::Log4perl for logging messag
+es

cpan shell -- CPAN exploration and modules installation (v2.14)
Enter 'h' for help.


cpan> h

Display Information                                                  (
+ver 2.14)
 command  argument          description
 a,b,d,m  WORD or /REGEXP/  about authors, bundles, distributions, mod
+ules
 i        WORD or /REGEXP/  about any of the above
 ls       AUTHOR or GLOB    about files in the author's directory
    (with WORD being a module, bundle or author name or a distribution
    name of the form AUTHOR/DISTRIBUTION)

Download, Test, Make, Install...
 get      download                     clean    make clean
 make     make (implies get)           look     open subshell in dist 
+directory
 test     make test (implies make)     readme   display these README f
+iles
 install  make install (implies test)  perldoc  display POD documentat
+ion

Upgrade installed modules
 r        WORDs or /REGEXP/ or NONE    report updates for some/matchin
+g/all
 upgrade  WORDs or /REGEXP/ or NONE    upgrade some/matching/all modul
+es

Pragmas
 force  CMD    try hard to do command  fforce CMD    try harder
 notest CMD    skip testing

Other
 h,?           display this menu       ! perl-code   eval a perl comma
+nd
 o conf [opt]  set and query options   q             quit the cpan she
+ll
 reload cpan   load CPAN.pm again      reload index  load newer indice
+s
 autobundle    Snapshot                recent        latest CPAN uploa
+ds

cpan> install Net::SFTP
Fetching with LWP:
http://cpan.strawberryperl.com/authors/01mailrc.txt.gz
Fetching with LWP:
http://cpan.strawberryperl.com/modules/02packages.details.txt.gz
Fetching with LWP:
http://cpan.strawberryperl.com/modules/03modlist.data.gz
Database was generated on Wed, 05 Oct 2016 03:13:43 GMT

Updating database file ...
Done!
Running install for module 'Net::SFTP'
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/D/DB/DBROBINS/Net-SFTP-0.10.
+tar.gz
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/D/DB/DBROBINS/CHECKSUMS
Checksum for C:\STRAWB~1\cpan\sources\authors\id\D\DB\DBROBINS\Net-SFT
+P-0.10.tar.gz ok
Scanning cache C:\STRAWB~1\cpan\build for sizes
......................................................................
+.....-DONE
DEL(1/6): C:\STRAWB~1\cpan\build\Type-Tiny-1.000005-k7jv4E
DEL(2/6): C:\STRAWB~1\cpan\build\Type-Tie-0.009-1AL1_9
DEL(3/6): C:\STRAWB~1\cpan\build\Hash-FieldHash-0.14-1AvrZF
DEL(4/6): C:\STRAWB~1\cpan\build\Devel-Caller-2.06-EDFLN7
DEL(5/6): C:\STRAWB~1\cpan\build\Devel-LexAlias-0.05-Kl44YI
DEL(6/6): C:\STRAWB~1\cpan\build\Type-Tiny-XS-0.012-BAZAfF
Configuring D/DB/DBROBINS/Net-SFTP-0.10.tar.gz with Makefile.PL
Checking if your kit is complete...
Looks good
Warning: prerequisite Net::SSH::Perl 1.24 not found.
Generating a dmake-style Makefile
Writing Makefile for Net::SFTP
Writing MYMETA.yml and MYMETA.json
  DBROBINS/Net-SFTP-0.10.tar.gz
  C:\Strawberry\perl\bin\perl.exe Makefile.PL -- OK
Running make for D/DB/DBROBINS/Net-SFTP-0.10.tar.gz
---- Unsatisfied dependencies detected during ----
----       DBROBINS/Net-SFTP-0.10.tar.gz      ----
    Net::SSH::Perl [requires]
Running install for module 'Net::SSH::Perl'
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/S/SC/SCHWIGON/Net-SSH-Perl-2
+.01.tar.gz
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/S/SC/SCHWIGON/CHECKSUMS
Checksum for C:\STRAWB~1\cpan\sources\authors\id\S\SC\SCHWIGON\Net-SSH
+-Perl-2.01.tar.gz ok
Configuring S/SC/SCHWIGON/Net-SSH-Perl-2.01.tar.gz with Makefile.PL
This is Net::SSH::Perl.

As of version 1.00, Net::SSH::Perl supports both the SSH1 and
SSH2 protocols natively. The two protocols have different
module prerequisitives, so you need to decide which protocol(s)
you plan to use. If you use one or the other, only those modules
for your chosen protocol will be installed; if you choose both,
all of the supporting modules will be installed. Please choose
the protocols you'd like to use from the following list ("Both"
is the default).

    [1] SSH1
    [2] SSH2
    [3] Both SSH1 and SSH2

Which protocol(s) do you plan to use? [3]

Checking for optional modules

Digest::BubbleBabble is required if you want to generate bubble babble
key fingerprints with pssh-keygen.

Would you like to install it? (y/n) [y]

Checking if your kit is complete...
Looks good
Warning: prerequisite Crypt::Curve25519 0.05 not found.
Warning: prerequisite Crypt::DH 0.01 not found.
Warning: prerequisite Digest::BubbleBabble 0.01 not found.
Warning: prerequisite String::CRC32 1.2 not found.
Generating a dmake-style Makefile
Writing Makefile for Net::SSH::Perl
Writing MYMETA.yml and MYMETA.json
  SCHWIGON/Net-SSH-Perl-2.01.tar.gz
  C:\Strawberry\perl\bin\perl.exe Makefile.PL -- OK
Running make for S/SC/SCHWIGON/Net-SSH-Perl-2.01.tar.gz
---- Unsatisfied dependencies detected during ----
----     SCHWIGON/Net-SSH-Perl-2.01.tar.gz    ----
    Crypt::Curve25519 [requires]
    Crypt::DH [requires]
    Digest::BubbleBabble [requires,optional]
    String::CRC32 [requires]
Running install for module 'Crypt::Curve25519'
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/A/AJ/AJGB/Crypt-Curve25519-0
+.05.tar.gz
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/A/AJ/AJGB/CHECKSUMS
Checksum for C:\STRAWB~1\cpan\sources\authors\id\A\AJ\AJGB\Crypt-Curve
+25519-0.05.tar.gz ok
Configuring A/AJ/AJGB/Crypt-Curve25519-0.05.tar.gz with Makefile.PL
Checking if your kit is complete...
Looks good
MakeMaker (v7.18)
Warning (non-fatal): Target 'dynamic' depends on targets in skipped se
+ction 'dynamic_lib'
Warning (non-fatal): Target 'static' depends on targets in skipped sec
+tion 'static_lib'
Generating a dmake-style Makefile
Writing Makefile for Crypt::Curve25519::curve25519donna
Generating a dmake-style Makefile
Writing Makefile for Crypt::Curve25519
"\x{0084}" does not map to cp437 at C:/Strawberry/perl/site/lib/ExtUti
+ls/MakeMaker.pm line 1269.
"\x{0084}" does not map to cp437 at C:/Strawberry/perl/site/lib/ExtUti
+ls/MakeMaker.pm line 1269.
"\x{0084}" does not map to cp437 at C:/Strawberry/perl/site/lib/ExtUti
+ls/MakeMaker.pm line 1269.
"\x{0084}" does not map to cp437 at C:/Strawberry/perl/site/lib/ExtUti
+ls/MakeMaker.pm line 1269.
"\x{0084}" does not map to cp437 at C:/Strawberry/perl/site/lib/ExtUti
+ls/MakeMaker.pm line 1269.
Writing MYMETA.yml and MYMETA.json
  AJGB/Crypt-Curve25519-0.05.tar.gz
  C:\Strawberry\perl\bin\perl.exe Makefile.PL -- OK
Running make for A/AJ/AJGB/Crypt-Curve25519-0.05.tar.gz
cp lib/Crypt/Curve25519.pm blib\lib\Crypt\Curve25519.pm
AutoSplitting blib\lib\Crypt\Curve25519.pm (blib\lib\auto\Crypt\Curve2
+5519)
cd curve25519-donna-master && dmake LIBPERL_A="libperl.a"       LINKTY
+PE="dynamic"      OPTIMIZE="-s -O2"       PREFIX="C:\S
TRAWB~1\perl\site"      PASTHRU_DEFINE=" "      PASTHRU_INC="-I. "
gcc -c -I.      -m32 -s -O2       -DVERSION=\"\"        -DXS_VERSION=\
+"\"  "-IC:\STRAWB~1\perl\lib\CORE"   curve25519-donna.
c
ar cr curve25519-donna.a curve25519-donna.o
rem curve25519-donna.a
Running Mkbootstrap for Curve25519 ()
"C:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command -e chmod -- 644 
+"Curve25519.bs"
"C:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- Curve25519.bs blib\arch\auto\Crypt\Curve25519\Cu
rve25519.bs 644
"C:\Strawberry\perl\bin\perl.exe" "C:\Strawberry\perl\lib\ExtUtils\xsu
+bpp"  -typemap C:\STRAWB~1\perl\lib\ExtUtils\typemap
Curve25519.xs > Curve25519.xsc
"C:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command -e mv -- Curve25
+519.xsc Curve25519.c
gcc -c  -I.     -s -O2 -DWIN32 -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT
+_CONTEXT -DPERL_IMPLICIT_SYS -fwrapv -fno-strict-alias
ing -mms-bitfields -s -O2         -DVERSION=\"0.05\"    -DXS_VERSION=\
+"0.05\"  "-IC:\STRAWB~1\perl\lib\CORE"   Curve25519.c
Curve25519.xs: In function 'XS_Crypt__Curve25519_curve25519':
Curve25519.xs:47:26: error: expected identifier or '(' before '[' toke
+n
         unsigned char OUT[32];
                          ^
Curve25519.xs:78:29: error: expected expression before ',' token
         curve25519_donna(OUT, csk, bp);
                             ^
In file included from C:\STRAWB~1\perl\lib\CORE/perl.h:5554:0,
                 from Curve25519.xs:2:
C:\STRAWB~1\perl\lib\CORE/pp.h:475:58: error: expected expression befo
+re ')' token
 #define mXPUSHp(p,l) STMT_START { EXTEND(sp,1); mPUSHp((p), (l)); } S
+TMT_END
                                                          ^
C:\STRAWB~1\perl\lib\CORE/pp.h:451:28: note: in definition of macro 'P
+USHs'
 #define PUSHs(s) (*++sp = (s))
                            ^
C:\STRAWB~1\perl\lib\CORE/pp.h:468:27: note: in expansion of macro 'ne
+wSVpvn_flags'
 #define mPUSHp(p,l) PUSHs(newSVpvn_flags((p), (l), SVs_TEMP))
                           ^
C:\STRAWB~1\perl\lib\CORE/pp.h:475:49: note: in expansion of macro 'mP
+USHp'
 #define mXPUSHp(p,l) STMT_START { EXTEND(sp,1); mPUSHp((p), (l)); } S
+TMT_END
                                                 ^
Curve25519.xs:80:9: note: in expansion of macro 'mXPUSHp'
         mXPUSHp(OUT, 32);
         ^
dmake.exe:  Error code 129, while making 'Curve25519.o'
  AJGB/Crypt-Curve25519-0.05.tar.gz
  C:\STRAWB~1\c\bin\dmake.exe -- NOT OK
Stopping: 'install' failed for 'Crypt::Curve25519'.
Failed during this command:
 AJGB/Crypt-Curve25519-0.05.tar.gz            : make NO


cpan> q
Lockfile removed.

C:\path to my folder\Perl scripts>perl -v

This is perl 5, version 24, subversion 0 (v5.24.0) built for MSWin32-x
+86-multi-thread-64int

Copyright 1987-2016, Larry Wall

Perl may be copied only under the terms of either the Artistic License
+ or the
GNU General Public License, which may be found in the Perl 5 source ki
+t.

Complete documentation for Perl, including FAQ lists, should be found 
+on
this system using "man perl" or "perldoc perl".  If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.


C:\path to my folder\Perl scripts>
[download]

Your forward progress seems to be stopped right now at a place that's not far from the beginning. When I see

C:\path to my folder\Perl scripts>

with spaces in the path, I think it's just waiting to break. I might start over without spaces.

I edited the output from the Windows command line window using Notepad++, replacing my real path with this made-up path name.

Everyone's path is different. As long as my machine knows where Strawberry Perl is, it matters not what particular path I execute my scripts from, as long as they can find the files that they need. In this case, it is just an installation.

I showed my attempt to install this module, because the original author of this thread was using Strawberry Perl and so do I, so our installations are virtually the same. In fact, I used Sandboxie, so as not to affect my real installation.

I see a couple things that might not be working here, so let me say that it's really important in Perl to get every keystroke correct, including capitalization.

I use strawberry perl, and to invoke cpan, I simply type

No 'sudo' here. Many treatments show that. To install a module:

There's a lot of SFTP stuff of cpan that is out-of-date. Read what they recommend as newest. Hope this helps

Thanks everyone for your time/suggestions.