The problem should be fixed -- I put in some changes yesterday which limits the maximum amount of workunits that can be in the database at any given time; since the server had around 300,000 WUs in the database when i made the change I put the cap at 400,000. Looks like you guys requested a ton more work and there are 400,000 WUs in the database at the moment. I'm going to increase the cap to 500,000 which hopefully should be more than enough.
The reason I'm putting the cap in is to prevent the problem we had earlier when I had to wipe clean the database. For whatever reason sometimes when the database is being backed up to disk or if there's a problem with the feeder, the code that calculates the number of workunits available fails and the work generator continues to generate new workunits without stopping -- flooding the database. This extra check should prevent that from happening.
Anyways, work should be flowing again shortly; and I'm working on a better solution to this problem then just a hard cap on the number of workunits in the database (although we probably need that to keep the database from getting unresponsive).