I've not got a 64-bit perl laying around, but a look at perllexwarn for 5.8.0 pointed me to the "portable" category, so that this might work:

use warnings;
no warnings "portable";
[download]

If it doesn't help, there might be some other category you can try in perllexwarn.

-- 
Joost       downtime n. The period during which a system
            is error-free and immune from user input.
[download]