Maybe it's just time to dump that WU then. Quoting instructions from a moderator at the other place:
Re: How to dump a WI in V7.
Postby P5-133XL » Wed May 09, 2012 2:36 pm
Record the number of the work queue for the particular WU. Pause or stop v7. Goto start->FAHClient->Data Directory->work and delete the folder that has the same number as the work queue. Restart v7. The client will clean itself up and get a new WU.