> I suppose two portable SBs in the path will lead to the primary searching for modules in the secondary

It is very disappointing but you are right (not for you, for the fact itself ;)

 perl -v

This is perl 5, version 26, subversion 0 (v5.26.0) built for MSWin32-x
+64-multi-thread 

# this perl has MCE support

 perl -MMCE -e 1

# and this is its path
PATH=C:\EX_D\ulisseDUE\perl5.26.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\c\bin;
C:\EX_D\ulisseDUE\bin\UnxUtils\usr\local\wbin;
C:\WINDOWS;
C:\WINDOWS\system32;


# this other one is 5.20.3 WITHOUT MCE

 perl -v

This is perl 5, version 20, subversion 3 (v5.20.3) built for MSWin32-x
+64-multi-thread

# original path

PATH=C:\EX_D\ulisseDUE\perl5.20.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\c\bin;
C:\EX_D\ulisseDUE\bin\UnxUtils\usr\local\wbin;
C:\WINDOWS;C:\WINDOWS\system32;

 perl -MMCE -e 1

Can't locate MCE.pm in @INC (you may need to install the MCE module) 
(@INC contains: C:/EX_D/ulisseDUE/perl5.20.64bit/perl/site/lib C:/EX_D
+/ulisseDUE/perl5.20.64bit/perl/vendor/lib C:/EX_D/ulisseDUE/perl5.20.
+64bit/perl/lib .).
BEGIN failed--compilation aborted.

# prepending the other version in PATH
set PATH=C:\EX_D\ulisseDUE\perl5.26.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\c\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\c\bin;
C:\EX_D\ulisseDUE\bin\UnxUtils\usr\local\wbin;
C:\WINDOWS;
C:\WINDOWS\system32;

 path

PATH=C:\EX_D\ulisseDUE\perl5.26.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\c\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\c\bin;
C:\EX_D\ulisseDUE\bin\UnxUtils\usr\local\wbin;
C:\WINDOWS;
C:\WINDOWS\system32;

# now... omg UPDATE: wrong assumption from my part: see below Anonymou
+s Monk at 11144117

perl -MMCE -e "print $INC{'MCE.pm'}"

C:/EX_D/ulisseDUE/perl5.26.64bit/perl/site/lib/MCE.pm
[download]

The wonderful cpanm program is problematic on windows: Re: Should cpanminus be part of the standard Perl release? -- MSWin32

I'd hardcode PATH inside the portableshell.bat

PS

if the alien perl is appended to PATH the beahviour is sane

set PATH=C:\EX_D\ulisseDUE\perl5.20.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.20.64bit\c\bin;
C:\EX_D\ulisseDUE\bin\UnxUtils\usr\local\wbin;
C:\WINDOWS;C:\WINDOWS\system32;
C:\EX_D\ulisseDUE\perl5.26.64bit\perl\site\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\perl\bin;
C:\EX_D\ulisseDUE\perl5.26.64bit\c\bin;

 perl -MMCE -e "print $INC{'MCE.pm'}; print @INC"

Can't locate MCE.pm in @INC (you may need to install the MCE module) (
+@INC contains: C:/EX_D/ulisseDUE/perl5.20.64bit/perl/site/lib C:/EX_D
+/ulisseDUE/perl5.20.64bit/perl/vendor/lib C:/EX_D/ulisseDUE/perl5.20.
+64bit/perl/lib .).
BEGIN failed--compilation aborted.


 which perldoc.bat

C:\EX_D\ulisseDUE\perl5.20.64bit\perl\bin\perldoc.bat
[download]

L*