There are more than one thing about this - But as You've done and used DVD+R before - first thought is
• Dust on the DVD-Burner Laser Lens - I use a DVD-Cleaning disk (with brushes - NO Liquid) now and then
• Cheap DVD Brands - Usually do not work as Memorex, NoName etc.
- I only use Verbatim
• DVD type - DVD+R is a more modern format and older DVD-players can not playback these
- I only use DVD-R (Never ever DVD+/-RW)
• Burn speed matters - full speed and many BURN ERRORS
- I always set this down to x2 or x4 - Plays on many more DVD-players
• Save as a DiskImage
- I always do - to see that all works as I like it before burning - then I use Disk Util tool or Toast™ to Burn
( This has ONE Major Advantage ! it splitts the DVD process into two parts and if anything goes wrong one can pin the problem to one of the parts )
• Free Space on Start-Up (Mac OS) Hard Disk
- for SL-DVDs I secure a minimum of 25GB free space - for DL-DVDs 50GB and if HD-Material is used about 4 - 5 times more to let iDVD and Mac OS run OK during Process.
Yours Bengt W