Anyone here have a Macbook Pro with DVD Studio Pro 4? I've been having an issue with blank discs. It says it can't read the discs that I've been using for a year now. Only blank ones have the issue, DVD's I've bought or already made work fine. When I try to burn a disc in DVD Studio Pro 4 it says "The disc cannot be recognized" with that annoying smiling Finder face... and then it says "one of the volumes on the media is still in use"

Any ideas for fixing this problem...this is ticking me off, it did this the day before I had to burn a different project, and I sent it off to be fixed for a different issue, and now its back. I really wanna throw this computer out the window. Any advice would be greatly appreciated.