I got it to work and I think I know the reason for the problem in the first place: my theory was that there was a semaphore of some sort that disallowed writing to the CD. First, the solution: I had Media Player in my taskbar. Right-click on the Media Player and run as administrator – you need only do this once. From that point onwards Media Player can be run as a normal user.
here's what I think the boys and girls at Microsoft did: have media player run normally. When I attempt to burn a CD, check to see if the device is in use. If it is give the error message and exit burn mode. Otherwise, elevate to admin, write the semaphore,burn the CD, remove the semaphore and de-elevate privileges.
The problem, I think, is if the burn CD process is interrupted: it leaves a "protected" semaphore that can not be removed from a normal process: only from an elevated process. If the semaphore had been written from the non-elevated process then this would not have been a problem.