Says chris2323:

WHAT THE HELL HAS HAPPENED TO LWP IN PERL 5.6.1?

Nothing. LWP is not distributed with Perl and never has been. You have probably configured Perl 5.6.1 to look for modules in a different place than 5.6.0 was, so it doesn't see that copy of LWP::Simple that you installed before.

Either reconfigure 5.6.1 to look in the right place, or copy all the locally-installed modules from the old library directory to the new one. The autobundle feature in the CPAN module might be useful if you need to copy the modules.