Thanks. The stated reason for busting my buy was that the underlying stock had a delayed open and the option should not have been trading. So 70 minutes after I had bought it and 30 minutes after I'd sold it, the initial buy was undone and I found myself short. After doing a third trade to cover, I wound up with a small net loss.
Watching a several hundred dollar profit taken away from you and turned into a potential loss has got to be one of a trader's worst nightmares.