There is a known bug with the SCCM MP and powershell/WMI v3 if you have the SCCM agent installed on your Management Point Server. When the SCCM agent health check runs nightly it rebuilds WMI and breaks the MP.
please see my follow up post here on how to setup a Configuration Item to find this on your network if you are running Pre SP1 ConfigMgr still.
I opened a case with Microsoft support they confirmed that there was a known bug with WMF 3.0 and SCCM MP. they had two options to resolve this
1. unisntall WMF 3.0 and uninstall the SCCM agent from the Management point Server (would need to uninstall and reinstall the MP after SCCM agent is removed)
2. edit the NotifyOnly Regkey to TRUE. full path to the Key HKLMSoftwareMicrosoftCCMCcmEvalNotifyOnly
They attempted to uninstall WMF 3.0 and reinstall the Management Point with the following steps