I’m trying to add the Grad College’s HP CLJ 2550n to printers. It goes OK until the end, where I’m uploading the Signed 200/XP/2003 drivers. I get an error “Unable to install printer. The print processor does not exist.”

Googling give a few helpful links:

An MS KB article with a hotfix:
http://support.microsoft.com/default.aspx?scid=kb;en-us;835609
However, we encountered this previously, and I thought we applied the patch. I will check the servers and try again before attempting any of the workarounds below.

HP Tech forum thread:
http://forums1.itrc.hp.com/service/forums/bizsupport/questionanswer.do?admit=716493758+1097772688984+28353475&threadId=288326

which points to a Microsoft KB article:
http://support.microsoft.com/default.aspx?scid=kb;en-us;275556

A thread on MSCE.MS:
http://www.mcse.ms/message183884.html
This looks more recent, though it predates googles first hit…