1) The current project that I am in has management servers that have Activestate Perl version 5.12 pre installed, but there are many Perl scripts which depend on it. I am treating it as a "System Perl" and do not want to fiddle with it. Access to the outside world is disabled from those servers. Hence I cannot also install required modules on it.

If you can't install a module on the machine, you can't install a whole new Perl either. If there is zero outside access, then you will have to type all your modules in by hand from a printed copy of the .pm.

Move the tarballs over and build them on the server, or see Yes, even you can use CPAN.