Seems like it stopped working after the upgrade to WordPress 3.1.2 but could have been before this but it was right around the same time.
Doesn't appear to be a memory issue as others are also appearing to have problems and I have WordPress and MySQL set for extra memory (I have the plugin set for 35MB). I've adjusted wp-config and another file on the server for more memory.
Trying to manually rebuild leads to a white screen. I've repaired and optimized the database, still no-go.