assuming in addition to SNMP TRAP Service it has the SNMP Service running also, try this in the Security tab for Accept SNMP packets from these hosts...
put the 'localhost' inside the SNMP settings. i've known this to work in some cases.
Alternative to what Ichance has suggested, you might want to check the SNMP service via services.msc, and also look at the Security tab.
[Start | Run | services.msc | SNMP Service]
Uncheck "Send authentication trap" if you do not need to see these authentication traps.
Thanks for info. I have checked this workstation, but it has no snmp service running or snmp was not installed on it.
Any other ideas?
it apparently does have SNMP TRAP service running then.
the next thing i would suggest is to do a sniff on the traffic and see if some system other than Solarwinds is attempting to do SNMP GETs to this IP address - this would generate Authentication Failures if it is trying to use an SNMP Community String not authenticated on the system.