Hi Tim,
SAPKB70015 is from March/2008. I think you will face issues with this low support package level. I searched for notes involving printing in WEBGUI and found notes that require a higher support package level to be implemented.
I would suggest to import a higher support package level (at very least SAPKB70022), then try again. If you consider raising a support incident, then use component BC-CCM-PRN-PC. (the HTTP trace will help the troubleshooting).
Regards,
Cris