Hi Robert,
I had the same problem but if you leave it for a day, then you will be able to delete it.
Here is the CISCO TAC reply for the problem.
Development team did some log searching and came out with the reply below:
"To delete a door, all associated events in live table needs to be deleted. This is handled when we give delete command for door from UI. For this door, there are some events associated was referenced by another internal table (vx_evt_q_state) for pruning activity. Hence these events were not deleted thereby door deletion failed. Subsequently when next pruning cycle run (which in Cu case is daily) the reference were removed. Thereby door got deleted."
Now why this internal table was left with some reference to this door can only be answer before the pruning happened (door deleted). So i would recommend you to contact us if this happen to any other door, so that development team look into it in current state.
Hope this helps.
Regards,