Kinda hard to troubleshoot this without knowing more information. What has happened since you originally had it installed? Did you reformat or did you delete the printer. Did you add a different printer driver? I'm also assuming you have Admin rights.
You may also wanna check out the Services in the Administrative tools section of the control panel and verify that the Print Spooler service is running.
It may also be possible that Windows XP has become corrupt or portions of the Windows registry (Hkey_local machine/Enum) have been write protected. You may want to check out the device manager to verify that there are not any errors on the USB UHC.
I have the same problem. I cant install the printer from the cd drivers or via win xp add printer. I origianlly received an rpc error so I made sure my rpc was on auto and started and double checked my spool as well. I also checked the usb and its fine. I also ran spf/scannow to no avail. Im stuck and would love some suggestions. thanks so much.