my buffer underrun always stays at zero when im burning a cd. any help is greatly appriciated

Moving to CDRW.

Is this with a new compilation from the hard drive or while copying on the fly?

i use one drive copy to hard drive then burn to cd but still stays at 0

Then it sounds like your hard drive is the problem. It's not delivering data to the burner fast enough. Defrag the drive and make sure that DMA is enabled for thr hard drive as well as the burner.
The burner could also be at fault. You should test it in another system to make sure it's working properly. It might not be buffering as it should. Try lowering the burning speed and see if that helps.
Try another burning program to see if the problem persists.