This is not a request for a answer, but help to others that might run into this.
While burning to Blue Ray Encore will hang, crash, and sometimes generate all but the burn given this situation.
I have a re-writable blue ray disk. If that disk had an error or you cancelled the burn and it was partial, there can be a condition on the blue ray that prevents Vista from sensing the device.
Once the disk is in this condition, you will experience slow response from everything on the system, including the my computer window, to encore hangs, crashes, timeouts, etc.
Exit all the applications, boot the system and remove the disk.
Once the system is back up, open the my computer window and put the disk back in and erase the disk by selecting the BD device and and right mouse click erase.
Once it is erased, you can resume encore burning, and system performance will go back to normal.
This one got me for a couple of hours until I saw the hangs system wide....
Also, you should update the Roxio component inside Encore
Fix Encore Win7 Problem http://forums.adobe.com/thread/528582?tstart=0 or direct to
Long File Names Cause Crashing http://forums.adobe.com/thread/588273
Plus some general reading