This is an interesting but unexpected result. With the Gutenprint also failing to print, it would suggest that something is amiss with your core printing system, namely the USB backend. This would explain why the test print via the Canon utility works, as it uses different communication protocols to invoke this print.
At this stage, since you would have already performed a reset printing system by following my steps, I suggest you download the OS X 10.5.8 Combo Update and run it. This has been known to resolve core printing issues.
If the update does not help, then there is a third-party utility called
Print Therapy that may get you printing again?
Just to be sure, I would also try another USB cable. I don't think this is the cause, but it is often overlooked as being the cause...