There are two possible causes:
1. By default the snmpcollector database, (a file called snmpcollector.mv.db), runs in embedded mode and allows only one connection. If that connection to snmpcollector fails, it does not allow another.
Error message in log:
/opt/nimsoft/probes/network/snmpcollector/SnmpCollector.mv.db failed; file length -1 read length 32 at 184866602
2. A known defect in the component.