PMP not starting for HPSIM Server

[Rob Buxton]

PMP 4.0.1, HPSIM 5.0
PMP is working fine over all of my Servers except for the HPSIM / PMP Host Server.
From the PMP Configuration screen the Server is licensed and started.
When I use the PF Link I just get the Unknown Performance Status Page with the links to Admin / Licensing.
I've stopped and restarted PMP from the config screen for the Server. Changed it from just Monitoring to Monitor, Alerts & Log.
Stopped and restarted the PMP Service.

Nothing has made any difference. I checked and rechecked SNMP and other protocol settings.

Not quite sure where next to look to try and track down why Monitoring is not starting.