I'm sure its frustrating, but I've not had problems burning discs in Encore, both single video discs and multi video discs IE using a menu to select which to play. I'm running windows 7, HP Z400, with an internal burner. The error message you had looks like a Mac issue. A Google search revealed many similar errors - not all related to Encore. I'm sure there are plenty of Mac users out there burning discs OK. It would be useful to hear from them.
Having said that, our Mac pro's are dual boot and I have had issues with them rejecting blank discs. IE tell Encore to burn 4 discs of a project, it burns one, wants the second disc, it takes it in and after a while it rejects it. I gave up and burned them in the Z400.
Maybe Adobe need to work on the Mac versions a bit more?
I provided the answer he describes above.
He sounded desperate, and rather than try to troubleshoot whether he can find a way to get his burner to work with Encore (many can't), I pointed to the quickest workaround,
PC users have as many problems with burning from Encore. Most of us don't bother. But we have ImgBurn.
The other thread is here:
While many Encore users DO use other burning utilities, and for various reasons, I have never had an issue with Encore burning on my PC's. This has been both DVD-5's, and DVD-9's.
About the only time that I use ImgBurn (for PC's), is when I wish to use my various multi-drives/burners, like a duplication tower, as I can launch ImgBurn several times, pointing each instance of that program to different multi-drives/burners.
Unfortunately, I know zero about Mac's, but if you would completely state the problems that you are having, plus the full details of your system, perhaps someone can help you solve the issues.