The following operating system updates are prerequisites for deploying Office Communications Server 20007 R2:

• Microsoft Knowledge Base article 953582, "You may be unable to install a program that tries to register extensions under the IQueryForm registry entry in Windows Server 2008 or in Windows Vista," at http://go.microsoft.com/fwlink/?LinkId=131392 .
  
  

This update must be installed before you install Office Communications Server 2007 R2 administrative tools. It applies to Windows Server 2008 and Windows Vista.

• Microsoft Knowledge Base article 953990, “AV at mscorwks!SetAsyncResultProperties,” at http://go.microsoft.com/fwlink/?LinkId=131394 .
  
  

This update applies to Windows Server 2003 SP2 and Windows Server 2008.