If you run a test trap from the Sim server itself does that work? Is the dataprovider SNMP or WBEM, switch to SNMP if you have'nt done so then look at your SNMP settings. If you could post a screenshot of your SNMP settings.
The later agents tend to be set on WBEM, that can also work, but then you would have to set the WBEM subscription. The subscription can be set from Sim under the option menu.