SBS2011 Monitoring reports not generated

Hi

This is a new SBS2011 migration from 2003.  Monitoring report generation has stopped working.

The MonitoringDataCollection task in the DataCollectorSvc never completes.  It starts at the first scheduled time as follows:

2013-03-10T18:01:03.43656 : Logger started at: 2013-03-10T18:01

2013-03-10T18:01:03.43656 : ***************** Starting MonitoringDataCollection task... *****************

2013-03-10T18:01:03.54576 : Details for domain computers collected from AD...

2013-03-10T18:01:03.842158 : Monitoring store updated with computer details...

2013-03-10T18:01:03.873358 : Details for domain users collected from AD...

2013-03-10T18:01:03.904557 : Monitoring store updated with users details...

2013-03-10T18:01:04.372556 : client computer TURING.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS018.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS017.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS009.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer crxsvr01.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer lectra2.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer BS58542.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer Lectra1.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS002.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS014.contoso.local is online.

2013-03-10T18:01:04.434956 : client computer SYS026.contoso.local is online.

2013-03-10T18:01:04.450556 : client computer SYS012.contoso.local is online.

2013-03-10T18:01:04.450556 : client computer SYS030.contoso.local is online.

2013-03-10T18:01:08.693756 : client computer SYS032.contoso.local is not online.

2013-03-10T18:01:08.693756 : client computer SYS025.contoso.local is not online.

2013-03-10T18:01:08.693756 : client computer SYS019.contoso.local is not online.

2013-03-10T18:01:08.740556 : client computer SYS008.contoso.local is not online.

2013-03-10T18:01:08.771756 : client computer SYS016.contoso.local is not online.

2013-03-10T18:01:08.849756 : client computer SYS006.contoso.local is not online.

2013-03-10T18:01:10.160156 : client computer SYS031.contoso.local is not online.

2013-03-10T18:01:10.160156 : client computer JAMESLAPTOP.contoso.local is not online.

but never gets any further, so that at the next scheduled time, and every scheduled time after that, you get:

2013-03-11T07:12:09.359372 : [MonitoringDataCollection] task has been cannot run due to conflicts with [MonitoringDataCollection] task.
2013-03-11T07:12:09.359372 : [MonitoringDataCollection] task cannot be skipped, now stay in the list.

I have run through all the usual checks and repair process, including recreating the monitoring database, WMI Diagnostics and WBEMtest - all these seem OK.

The next thing the MonitoringDataCollection task should be doing after enumerating the computers is WMI data collection.

How can I fix this please?  I would like to repair or reinstall the DataCollectorService but the advice in the Repair Guide applies only if the service does not exist.

Any help would be appreciated.

Thanks

Jim