Perl 5.8.1 should not be used any more, because of binary incompatibility with 5.8.0. It is the reason why 5.8.2 came out so soon. So, use either 5.8.0 or 5.8.2.

I've been told that in ActivePerl/Win32, the feature responsible for the incompatibilty, had been disabled. So ActivePerl 5.8.1 is fine.

Perl 5.8.2 and later will be binary compatible with 5.8.0, and largely also with 5.8.1.