@David: "Printer is busy" means it's not really getting access properly. Are you sure your IP address is set properly on your printer? You need to make sure that you are using the right IP address range for your network too, my example of '192.168.0.4' works on my network but other networks may use a different IP range such as '192.168.1.4' or '10.0.0.4'.
The printer driver location for me is the following:
You may not need the 'en/lproj' containing folder but that's where I have mine.