I had this and ended up switching off GigPress.
Having switched off loads of plug-ins to get things like the site to reappear, then to get posts usable, and now to get pages working again, i’m left with just Akismet, Google Analytics and a Facebook Fanbox. I’ve had to switch off all the Twitter and Sociable plug-ins just to make the site usable again.
I guess the plug-ins will eventually get a revamp which will make them stable for use again with WP 3.0.