Discus printing issue with Canon i960


I'm using Magic Mouse's Discus 3.13G for creating CD labels and printing to a Canon i960. I run Mac OS 10.4.2 on a 15.2-inch G4 1.5 GHz PowerBook with 768 MB RAM.

Recently I started experiencing a strange problem that when I run a couple programs at a time and switch back to Discus, my printer stops printing. It tells me that the print queue has stopped. When i try to start jobs again, it stops again. The only way to get past this is to reboot the whole machine.

Any ideas? Please help. Thanks!