What does "perl -V" tell you?   That is, where does the newer Perl think it should look for modules?

On my RH7.2 Perl 5.6.1 system the last part of the output reads:

  Compiled at Feb 20 2002 15:01:16
  @INC:
    /usr/lib/perl5/5.6.1/i386-linux
    /usr/lib/perl5/5.6.1
    /usr/lib/perl5/site_perl/5.6.1/i386-linux
    /usr/lib/perl5/site_perl/5.6.1
    /usr/lib/perl5/site_perl/5.6.0/i386-linux
    /usr/lib/perl5/site_perl/5.6.0
    /usr/lib/perl5/site_perl
    .

On another system, RH8.0 with Perl 5.8.0, it reads

  Compiled at Sep  1 2002 23:56:49
  @INC:
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.0
    /usr/lib/perl5/vendor_perl
    .

Check out your directories to verify modules are getting installed where you expect.   Also, a trick I saw here helps me when I'm wondering if I'm 'seeing' the module I just installed.   If you've just installed Acme::WhatZit version 3.14 try
    perl -M'Acme::WhatZit 9'
That should complain saying it doesn't have version 9, that it only has version 3.14.   That's just one more way to be sure. Of course, if it complains:
    Can't locate Acme/WhatZit.pm in @INC (@INC contains: /usr/.....
then you know your Perl can't find the module in any of the places it expects them.