Well, I've de-modularized my code for the momen, but I was able to recreate the problem by adding require "base"; back at the top.

The error message is as follows:

Can't locate base in @INC (@INC contains: ./focus /usr/opt/perl5/lib/5.8.0/aix-t
hread-multi /usr/opt/perl5/lib/5.8.0 /usr/opt/perl5/lib/site_perl/5.8.0/aix-thre
ad-multi /usr/opt/perl5/lib/site_perl/5.8.0 /usr/opt/perl5/lib/site_perl .) at s
l_observe.pl line 8.

(Although, as per the second comment, using require base works just fine.) The error message was the same for Nfs.pm; however, Nfs_module.pm was found. I was having more problems (specifically getting the variables I'm using exported correctly) so, for the sake of getting the code to production level, it's currently de-modularized.