First, let me say that I've used version 0.4 of the importer on WP 3.1.3 with complete success. I downloaded ver. 0.5 this morning, and installed it on my test blog (WP ver 3.2.1). I've been working on a new theme for this blog, and up until I installed the importer, everything was working fine. As soon as I installed the importer, I started getting errors in the admin area and the site index page is completely blank now.
I determined that the culprit was the importer by deleting all the WP files and database tables, then reinstalling WP, followed by a fresh install of the importer. I did this twice, just to be sure. I activated my custom theme the first time, and used twentyeleven the second. There was no difference...I got identical errors and results (blank index page) both times.
Just thought you should know that it's doing this...No big deal for me, I'll just install WP again and not worry about importing test content. :o)