I'm doing a similar job, authoring video DVDs for artists, from various video or audio sources.
I'd suspect the burning software to be responsible in your case. I've had issues when burning VOB/IFO files directly, specially with Nero.
To avoid any issues, I now open the authored DVD files in DVDShrink and create an ISO that I burn with IMGBurn.
- Shrink re-encodes the files (100% lossless if no compression is required) so you can be pretty sure that the final result is compliant.
- The ISO can be checked for readability (with Daemon Tools and Windows Media Player for example)
- Burns of ISO with IMGburn are far less problematic that direct burns of the raw, discrete files. Don't know why, though.
I hope I'm making some sense, I'm very tired :bigsmile: