In short, it sounds like you have a bad version of XML::Twig, and you should grab it from CPAN and reinstall it.
The long answer is that perl modules must end with a true value (most modules simply put 1; at the end), but the XML::Twig that you have installed doesn't do that (which leads me to believe that you have a bogus version). For more information on the whole must-return-a-true-value thing, see perldoc perlmod."One word of warning: if you meet a bunch of Perl programmers on the bus or something, don't look them in the eye. They've been known to try to convert the young into Perl monks." - Frank Willison