Error message when you try to send an instant message in Communications Server 2007: "The following message was not delivered to <recipient>"

When you try to send an instant message in Microsoft Office Communications Server 2007, the recipient cannot receive the instant message. Additionally, you receive the following error message: Additionally, the following event is logged in the Communications Server 2007 log:

Event Type: Error
Event Source: OCS Intelligent IM Filter
Event Category: (1025)
Event ID: 41006
Date:
Time:
User: N/A
Computer: Server Name
Description: Unable to load settings from WMI
Exception: Object reference not set to an instance of an object.
Cause: The Office Communications Server Intelligent IM Filter application is incorrectly configured or application does not have permissions to read WMI.
Resolution: Verify that the RTCSRV service account has read permissions on WMI and that the MSFT_SIPIIMFilterUrlFilterSetting and MSFT_SIPIIMFilterFileFilterSetting classes are correctly configured. For more information, see Help and Support Center at <http://go.microsoft.com/fwlink/events.asp>.

To resolve this issue, follow these steps:

1. Open the Communications Server 2007 Microsoft Management Console (MMC) snap-in.
2. In the console tree, expand the forest node, and then use one of the following procedures:
   • For an enterprise pool, expand Enterprise pools, right-click the pool, point to Application Properties, and then click Intelligent IM Filter.
   • For a Standard Edition server, expand Standard Edition servers, right-click the pool, point to Application Properties, and then click Intelligent IM Filter.
3. In the Office Communications Server 2007 Intelligent IM Filter dialog box, click Restore Defaults.
4. If you do not want to block URLs, click to clear the Enable URL filtering check box.
5. Click OK.
6. Stop and then restart the Communications Server front-end services. To do this, follow these steps:
   1. Click Start, click Run, type services.msc, and then click OK.
   2. Right-click Office Communications Server IM Conferencing, and then click Stop.
   3. Right-click Office Communications Server IM Conferencing, and then click Start.
   4. Repeat steps 6a through 6c for the Office Communications Server Front-End service and for the Office Communications Server Telephony Conferencing service.