Hi Robert,
Ok, in that case, let’s first rule out the most common possibilities that would have caused that to happen.
Can you confirm with me you’ve done all of the following? Once I know for sure I can get higher level support on this if needed:
1. Are you running the latest version of WordPress?
2. Are you running the latest versions of our plugins (2.0.8)?
3. Have you tried deactivating all other plugins to rule out a conflict?
4. Have you tried reverting to the Twenty Eleven theme to see if it’s something with your theme?
5. Try setting your permalinks to ‘postname’ in Settings > Permalinks?
6. Try refreshing your permalinks by visiting Settings > Permalinks (it does it automatically)?
7. Try increasing the PHP memory for your website: http://www.dailyblogging.org/wordpress/increase-wordpress-memory-limit/?