Categories not working

My blog is 2.0.2 It is found at:
http://www.marialiberati.com/blog2
We moved it over from a yahoo hosting to hostmonster.com account-ever since the move the categories and the archive of blogs listed on sidebar do not work. When you go to categories or archives nothing comes up but a blank page. Any help or ideas appreciated. It has been 3 months that this has been going on.