SP2 has some changes in the way SNMP is handling printer queues. It now does multiple SNMP threads for the printer queues instead of 1 round robin. To resolve this, check if your printer's SNMP is working properly.
To workaround, in the Printers and Faxes folder,
File > Server Properties Goto Ports Tab > Click the offline Port > Configure Port
Uncheck "SNMP Status Enable"
OK
This will turn off SNMP querying and set the printer to always Online.
This is essentially disabling the detection of printer state, but it will allow the printer to work. This only effected some of my Canon copiers not HP or Xerox printers.
I was experiencing this problem, and I was able to get the SNMP monitoring function working after some further configuration.
Many people do not understand the nature of this problem and are copying your information and representing it as a 'fix'. Here are the additional steps required to retain the monitoring on a printer:
1.) Configure the SNMP community name in the printer port and have a matching community name configured in the printer. This may need to be a read/write community name, test read only and read/write on your device to determine what is required.
2.) Configure the SNMP device index in the printer port according to your printer documentation. Most printers are '1', but multi-function devices are not.
3.) On your printer, configure the IP address of the server/workstation where your RAW/LPR port is defined as an SNMP manager and/or trap-recipient IP address as required by your printer.