Constant error on client 2008 Servers "Module was unable to connect to namespace 'Win32_LogicalDisk'"

Thanks for reading.

I've inherited a SCOM 2012 environment and I'm trying to resolve some client errors on 2008 servers.

This error is occurring on many 2008 R2 servers.

Log Name:      Operations Manager
Source:        Health Service Modules
Date:          14/11/2013 8:51:44 AM
Event ID:      10401
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      MyServer.InOurDomain.com
Description:
Module was unable to connect to namespace 'Win32_LogicalDisk'

 This has happened 285 times since this instance was loaded.

 HRESULT: 0x8004100e Details: Invalid namespace

One or more workflows were affected by this. 

Workflow name: UIGeneratedMonitor463cdab8ccb4471985ceb4a27c1567a6
Instance name: MyServer.InOurDomain.com
Instance ID: {F438A6BD-42FB-3299-9D70-0D76303343D1}
Management group: SCMOPS2012

I've looked for a bad custom rule but cannot seem to find any. I am a novice with SCOM.

Geoff.