++

As a sysadmin and perl user, I've run into similar problems before and they almost always stem from multiple perl binaries installed. You can also get into multiple copies of cpan, and you can get cpan behaving differently depending on what user you log in as. And which of your multiple binaries is cpan executing?

More concretely, look for /usr/local/bin/perl and /usr/bin/perl. Run "which perl" and "which cpan". Scripts usually have a path in the 1st line, like "#! /usr/bin/perl" so if you have a /usr/local/bin/perl and a /usr/bin/perl and your scripts start with "#! /usr/bin/perl" and your $PATH has /usr/local/bin/ before /usr/bin, you'll be calling the a different binary from the command line than when you execute scripts. E.G. "perl -Mcpan -e shell" would run under /usr/local/bin/perl, while running "cpan" might run under /usr/bin/perl.

If you're compiling your own perl, make sure you know where it lives and make sure you call it with the full path and make sure cpan calls it as well. It might even be a good idea to put it outside of the usual path (/usr/local/mybin/perl, say), so you know for sure when you call it or the distro installed version. I always keep one and only one perl binary on my systems to avoid this problem.

Good luck!

--Pileofrogs

Currently, it's using perl 5.10 which I'm fairly certain is the same version prior to the server upgrade. I'm not sure which libs have changed because unfortunately, it's not something that I've paid much attention to until it breaks. My bad. Here's the results of perl -v:

Summary of my perl5 (revision 5 version 10 subversion 0) configuration
+:
  Platform:
    osname=linux, osvers=2.6.26-2-amd64, archname=i486-linux-gnu-threa
+d-multi
    uname='linux puccini 2.6.26-2-amd64 #1 smp fri aug 14 07:12:04 utc
+ 2009 i686 gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dccc
+dlflags=-fPIC -Darchname=i486-linux-gnu -Dprefix=/usr -Dprivlib=/usr/
+share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dve
+ndorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/us
+r/local -Dsitelib=/usr/local/share/perl/5.10.0 -Dsitearch=/usr/local/
+lib/perl/5.10.0 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/ma
+n/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man
+/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Ua
+fs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2
+ -Duseshrplib -Dlibperl=libperl.so.5.10.0 -Dd_dosuid -des'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=und
+ef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict
+-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFS
+ET_BITS=64',
    optimize='-O2 -g',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing
+ -pipe -I/usr/local/include'
    ccversion='', gccversion='4.3.2', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=1
+2
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
+ lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib /usr/lib64
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.7.so, so=so, useshrplib=true, libperl=libperl.so.
+5.10.0
    gnulibc_version='2.7'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY PERL_DONT_CREATE_GVSV
                        PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP USE_ITH
+READS
                        USE_LARGE_FILES USE_PERLIO USE_REENTRANT_API
  Built under linux
  Compiled at Aug 28 2009 22:15:29
  @INC:
    /etc/perl
    /usr/local/lib/perl/5.10.0
    /usr/local/share/perl/5.10.0
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.10
    /usr/share/perl/5.10
    /usr/local/lib/site_perl
[download]

The system admin said he saw several perl updates at the end of the install of 300+ packages. I'm assuming that whatever packages it installed, it either uninstalled the packages (or at least doesn't show them as installed) or reset some config file somewhere.

In defense of the sys admin, I barely know what I'm doing and I'm the perl programmer! I'm not expecting him to know more about perl than me.

Anywhooo...So since the perl was upgraded, am I better off reinstalling the modules, or can I simply point to the existing modules? What is the best practice here?

As different major versions of Perl (such as 5.8.x vs. 5.10.x) are not binary compatible, you need to reinstall XS modules (those which are not pure Perl).  Pure Perl modules should continue to work, but you might want to check anyway whether there are new versions available (with bugfixes, new features,...).