Daniel,
The reason you don't get an exception when the dwg is CLOSED is because of this line:
controlDB.ReadDwgFile(plotControlDWG, System.IO.FileShare.Read, false, string.Empty);
The FileShare.Read is telling it that you want to LOCK the file, read it and only allow read access to others...hence if you have it open, it's already locked and your code can't get an exclusive lock.
Kerry and others,
Are you still having trouble findinng an optimum solution for this? If yes, create a template file with some named pagesetups in it, then post back and we can have a little lesson/experiment.
I won't do this if there's little interest.
Cheers,
Glenn.