I do everything u discribed while burning onto Traxdata, DVDMaster and ritek and get perfect burn every time.
Thats what buffer under-run protection was designed to do!!!!
I think it is either a media issue or a laser problem in yr PS2.
R U burning at correct speed for media?
Although people recomend that u burn as slow as possible, this is just a habit from PSX and burning CDR.
On some media rated at 2X if you burn at 1X u can over cook the write surface and make the dvd-r very difficult to read.
Simple answer, get a ritek or traxdata, turn all other progs off, use recomended software ( Primo2 or record max now) and burn at recomended speed and see what u get out.
Everyone seems to have one problem or another to iron out when burning dvd-r's. Mine is that I have to have my pioneer 104 on an IDE cable on its own. If i plug anything into the slave socket on IDE 1 it has snags so effectively I have lost an IDE device on my PC but wot the Hey, I burn all the dvd's i want for that small drawback!!
Regards, Hope u get it sorted, feel free to pm me for any advice!!