[TheMamba]

Spend the few bucks and get the complete Nero burning program. It's worth it and you'll be using it all the time.

The only other thing I can think of is that your computer is having to transfer data from an external HD, to the internal drive, and back out to an external writer. That's a lot of transferring and every transfer lends itself to errors...especially when burning on the fly like that.

If I were you, I would first copy whatever I wanted to burn from the external hard drive to the internal hard drive and THEN burn. See if that helps out at all.