Hi Steve1313, welcome to CDF
I'm guessing those GQ discs are regular single-layer discs, and whatever you are backing up (movie?) is on a dual layer disc, and there isn't enough space on the destination disc.
If it is a movie you're backing up, you'll need to shrink it so it'll fit onto a single-layer disc, or use a DL disc (I recommend Verbatim for dual layer).
A bit more detail - i.e. what it is you're trying to back up etc, would be really handy