Scott Hanselman ran into a critical bug in dasBlog 1.6 that has to do with the new caching logic that the folks in the GDN workspace came up with (I didn't do it, I didn't do it!). We've both sent email to those who know about this issue and will see who will look at it and when. Apparently Scott posted something using an external tool and a couple of things were happening in parallel around that same time and that got the caching mechanism confused. If you get unexplicable errors and all you get is the "error page" , go ahead and delete the files entryCache.xml, categoryCache.xml, and blogdata.xml; then open and save (touch) web.config. that should get the blog back on its feet.
If you are on version 1.5 or earlier, stick to it while this is being checked. If you are on 1.6, have some tea or a lightly alcoholic beverage and don't panic.