OK, here's what I discovered...
First off, you don't have to leave the application open. I put the DVD in, set the bitrate to DVD-ROM and closed the app. After my burn was done with DVDShrink, voila...it's bookmarked as DVD-ROM.
Now the very bizarre. The first time I tried it by leaving the app open, it 'shut down' my second hard drive.
My setup is like this. I have W2K with two 120G drives. My second (F) is for saving DVDShrink folders/files. Sometimes I burn directly to disc, others I shrink to folder and then move folder to disc. In this case I had already done a shrink and was now going to use Shrink to move the folder ("Open Files") onto the disc.
I started by putting the DVD+R into the burner (my D drive) and doing the bitset, leaving the app open. I then started DVDShrink, reading files on my F drive with temp file caching onto my C drive. Well, about part-way into the process I got a message that a file on the F drive wasn't available, that access was denied. All of a sudden my F drive acted like it was a local drive that wasn't there. I'm an Admin on my system and the drive was for all intent and purposes...gone.
Freaked me out! I thought someone had hacked into my system! I rebooted and it came back. Then I started thinking that maybe the Bitset utility had something to do with it. Sure enough, when I repeated the steps it happened again...even without DVDShrink running; the F drive just 'went away'. If I closed out the bitset app then the drive freed up and was available again. STRANGE!!!
Running the app, setting the bitset and then closing the app (keeping the disc in all the time, mind you) worked just fine.
Marco, if you read this, you may want to check it out. Maybe something to do with my drive ordering? C -> D (DVD being set) -> F (drive affected)