Samsung DVD-R120 disc errors - help please

[headlessagain]

I am getting repeated disc errors - reading,writing and formatting DVD-RW and RAM discs.Tried to delete title from DVD-RW and error message
"(EC 0533) System Error is found.Please try it again after turning off power"
When formatting reached 85% then reports "You could not format the disc because of error detection" Also fails to delete titles. Commercial DVD play OK.
Out of frustration formatted all my discs in my PC LG drive but now get Uniitialized disc message but fails when I say yes to it.
I have installed the latest firmware but still no change. The weird thing is that I changed from Datawrite media to Verbatim as I started to experiance errors with the Datawrite discs. I'm now getting the same problems with the Verbatim discs but the Datawrite discs(tried 3 so far )seem the record,delete,format etc perfectly. The verbatim discs are in better condition and newer than the Datawrite media.
Any ideas out there?
Tanks
Andy