use base is new syntax, introduced with Perl 5.004_04, so it should work with your 5.005_03.
You have to type less, and the intent is clear immediately.

It will require the module if needed, and will push it onto @ISA. It will do some other things as well - read the manual.

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
[download]