Irritating print problem

I'd be very grateful for any advice anyone can give me on this one...

When printing, intermittently the document stops outputting to the printer queue about 20% of the way through. The only way I can fix it is by unplugging the USB printer plug, plugging it back in (straight away), and then clicking on 'Start Jobs' in the Print Queue. This happens about 50% of the time.

My setup is:
Computer: MacBook Pro
OS: OS X v 10.4.8
Printer: HP LaserJet 5L
Connection: USB-to-parallel lead
Driver: Gimp Print v 5.0.0 beta2

I realize that the word 'beta' is a warning, and that this is an unsupported hardware/software setup but, as it works half the time, it's just frustrating that it can't work all the time. I doubt it does the USB port much good being unplugged and plugged back in several times a day.

Any advice would be much appreciated!