I really hope the print server gets it working for you then. You are quite technically advanced so I am sure you will give me a run for my money when you return. I will continue to review your current setup for any hints that may lead me to offer a suggestion you have not done yet.
If you have done a lot of steps, were you able to confirm that the USB port in the back of the printer is working? Meaning, since it is not installing on two different computers, were you able to get it to register at some point since you started having this problem?