The version of MakeMaker in perl 5.6.1-r7 seems to install modules underneath /usr/lib/site_perl/5.6.1, which is not in @INC, instead of under /usr/lib/perl5/site_perl/5.6.1, which is where previous versions put things. All modules that use MakeMaker installed after a 5.6.1-r7 upgrade become unusable. Remerging ExtUtils-MakeMaker manually afterwards fixes the problem.
Robert, Thanks for the post! The r7 was *supposed* to include the corrected MakeMaker in it, and did during testing. I've included seemant on this bug since he helped me set up that ebuild. Will look into it very shortly. Thank you!
updated in portage. it seems the -r7 didn't have the requisite fixes...