the_slycer,
Actually I assumed you did have:

#!/usr/bin/perl -w
use strict;
[download]

In the small snippet you showed on 5.6.1 you would not have encountered any problems. That is why I didn't specifically mention them. This is because the strict pragma ignores $a and $b since Perl uses them to allow you to build a custom sort routine.

Cheers - L~R