possibly, but not likely. Try another cable just to check.
Is there anything in particular you did to make it happen? e.g. upgrading to Nero 8, upgrading hardware/software etc.
EDIT: Just thought about it some more; when your burning, what are the buffers like? they should be between 80-100%. If it's erratic that means it's having trouble getting the data fast enough.
Are you burning from an image or from another drive?