Ok, this is a brute-force method of resetting she Share Monitor queue, but it was the only one that worked for me. I found that if I restarted my machine and then once it restarted and before running FCP X or Compressor 4 I deleted everything from the following folder, this cleared all job information listed in Share Monitor (everything, not just the logs):
~/Library/Application Support/Apple Qmaster/
This fixed a problem I was seeing where a job would get to the point where it finished transcoding, and then would sit in the queue forever with a status of "Finishing". There was a previous job in the queue that had failed and I tried to cancel it, but it got 'stuck' in a "Cancelling" state. I think this had something to do with the fact that none of my other jobs would finish from that point on.
Anyway, clearing out the contents of the previously mentioned folder appeared to reset that queue.