After I installed Windows 2003 SP2 on one of my client's Windows 2003 Server which was also a print server the printer queue went offline.
I would restart the Print spooler service on the Server and the printer would stay online only for 1 job, and it would go offline immediately after 1 job.
After researching for over an hour I found out that apparent SP2 has some changes in the way SNMP is handling printer queues.
It now dows multiple SNMP threads for the printer queues instead of 1 round robin.
To resolve this, check if your printer's SNMP is working properly.
For a workaround, in the Printers and Faxes folder
File => Server Properties
Go to the Ports tab
Click the port that is going offline
Uncheck "SNMP Status Enable"
PS: This is a workaround only, after I have found out a permanent fix to the situation I will post it here.
This will turn off SNMP querying and set the printer to always Online.