Private Job printing with defaults defined on print server

[Heiner E. Lennackers]

G'day Everybody.

I have a problem and i hope someone can help me.
I have a few HP CLJ 5550 printers, connected to a windows 2000 print server. In the printing defaults "Job Storage Mode" is set to "Private Job" with "Windows User Name" as "User Name", automatic Job Name activated and a default PIN set.
When a User on a client prints now a Jobs to one of these printers sometimes not the users windows name is used but the print server administrators name. This is not static. A user and/or client who did not have this problem may have it a day later and vice versa.
How can i prevent this? (Disabling Private Job is not an option, because it is a company policy to have this enabled)

TIA
HeL