Ok, that's true for releases before 5.8.8 build 818 or so. In Perl 5.8.8 ActivePerl switched to PPM4 which allowed updating core modules by putting them into site/lib, so the order of directories in @INC had to be changed to make this sane.

Generally I try to pretend that Perl versions less than 5.8.8 do not exist anymore. Sometimes I even succeed. :)