I’ve been having problems burning DVDs with Ubuntu 8.04 (the AMD64 version) for the past couple of weeks.  I found the “all_generic_ide” fix online which seems to have fixed the problem when burning data DVDs from Brasero, but I’m still having problems burning isos from Gnome.
Ubuntu sees the DVD burner as “ATAPI: HL-DT-STDVD+-RW GSA-H31N, B109, [...]