Vcenter Server 5.5U2 No CIM on ESXi4.1 host

I have just upgraded to a Vcenter Server 5.5u2 from 5.5u1a .

All functions work apart from hardware monitoring on my ESXi4.1 host. The other host is 5.5u2 and that reports fine. The ESXI also reports with a direct ViClient connection.

I have checked Ports and also restarted the CIM service on the HOST

Error is: "Hardware monitoring service on this host is not responding or not available" I have checked KB1013080

I guess this must be a 5.5U2 Vcenter Server issue, any one had a similar issue, I cant finad any references.

Tony