Try different CDRW media .. burning at a lower speed ... increasing your burning buffer .. ensure that UDMA is enabled for the drive, and also ensure that it creates an image (aka buffers to HD) first.
Also CDRW media deteriorate, so if it's an older CDRW disc, it won't perform as cleanly as a new CDRW disc will.
But please explain what the burner is, where it is located, and what media you are using ... the nero infotool will tell use everything we need to know.
I've had the issue with various CDRW as well, brand new. Rewritable media is just not good for storing uncorrected data
Please save the Nero->infotool log (minus your registered user info & serial number) and post in "[ Code ]" & "[ /code ]" tags here.