So strange…I’ve used Verbatim, TDK, and Memorex discs, have made sure that I have lots of RAM available (3-4GB free while burning), have 160 GB of free space on my internal hard drive, have the bit rates in both Compressor and DVD Studio Pro matching (the standard bit rates that come up under Best Quality DVD: 90 minutes in Compressor of 6.2 and 7.7), have un-checked lossless linking. I’ve tried it in iDVD as well, and that doesn’t solve the problem either. Maybe my burner needs cleaning, or needs to be replaced or repaired? That’s about all I can think of at this point.