First, welcome to the forum. Next, what is your firmware, what software are you burning with at what speed, and is this a new problem or is the drive install fairly new?
My best guess would be you don't have an 80 wire cable. It is possible you have a conflict with IDE drivers unless you are using the MS version.
MCC 004 are some of the best discs around, with a few exceptions. They burn best at 12X on the Pioneers, sometimes at 8X.