Sorry, this isn't an answer to your problem.
I've been doing the same thing. Or at least similiar.
I have a Mac Mini with a red laser and Toast 11.0.1.
I've been burning to DVD-R my film collection, which consists of old SF films in various formats. DivX, AVI, Generic-MP4, MP4, M4V etc.
I'd start Toast 11; then select DATA -> DVD-ROM(UDF) -> create a disc name add the various movie files.
Each time I'd burn the project to a DVD+RW disc first and check it was OK, before burning to a DVD-R.
I'd test the DVD-R's in my Sony BDP-S370 Blu-ray player, which has the latest firmware installed.
I burnt 5 DVDs with no problem. All films play without a problem.
Then when I tested the DVD+RW from the latest project I'd got a DVD symbol with a "?" across it.
The blu-ray player couldn't play the DVD. ie; could not read DVD.
I've been trying everything I can the last day or two to correct this problem, up to and including re-installing Toast 11.
With odd results.
I burnt two films to a DVD+RW using the above process and it worked fine.
Video Tracks: Generic MPEG-4, 1280 × 720, 23.976 fps, 2.94 Mbps
Audio Tracks: AC3, 48 kHz, 384 kbps
Video Tracks: H.264, 1920 × 1080, 23.976 fps, 2.37 Mbps
Audio Tracks: (ac-3), 640 kbps
Then when using the same process again to burn some other films, it failed with an unreadable DVD.
I'm perplexed as to what's going on. I think it's either similiar too or thee same issue as above.
Any information gratefully received.