ok, so my site is running normally again. I subscribe to a security service that scans my site for malware usually, but the guys also fixed the site now again. I could not follow the procedure, but it had to do with recreating the htaccess file disabling/reenabling plugins. Took about 10 mins to fix. The guys are at sucuri.net. Other than that, I found this page:
http://themeforest.net/forums/thread/custom-post-types-and-permalinks-in-wordpress-31-rc/39380
I have no idea what flushing means, though.
Here is the issue:
i upgraded to 3.1 and i suddenly got 404 errors. if i revert back from the permalink to standard urls, the site works fine, but the custom permalink results in a 404 error. and the previous links are not redirected to the new urls. it seems there is somethink that manually flushes the rewrite rules. and i have no idea how to do that.
