Something certainly seems wrong. I doubt it's your burning software itself. I'll second the fact that Mint in general does not have burning issues. My experience is that any issue I've ever had in Mint I've also had in Ubuntu. For example K3B in a Gnome Environment (not KDE) gives me issues if I want to use burn proof. After a successful burn the disk ejects like it's supposed to, but the drive does not pull it back in, and the verification fails. The burn itself works, but the verification doesn't happen unless it was an .iso file I was burning, and for some reason those burns will. I've had this issue in both Ubuntu and Mint with K3B. So my experience leads me to believe that their is no difference between Mint and Ubuntu when it comes to burning.