Try uninstalling and reinstalling the software, it might just be a glitch.
I have been using a Canon MP810 to print on CD's and DVD's, which up to now has worked very well. However just recently it will not print on the disks with no apparent reason, nothing has changed to my knowledge. The tray with the disk goes into the printer ok when prompted to print but it comes out again without any printing on it. The printer comes up with a message Error No. 1001 CD-R tray is not inserted or a printable disk is not placed on the CD-R tray, load a disk insert the tray along the guide rail and press the ok button on the printer. Printing will restart.... Well it does not, no matter how often you try. Can you help? Regards Fred2794