Compressor going psycho... feel the love.
You may already have, but search Apple.com threads for this. There are usually some handy links within those discussions.
The only solution that ever worked for me was going into the terminal and starting qmaster from there:
sudo /Library/StartupItems/Qmaster/Qmaster
It's a temporary fix, like you said, but it works.
Hopefully someone might be able to provide a more permanent solution.