Installing OCS 2007 R2 on Windows 2008R2

If you try and do the install it will fail (or appear to do nothing) on installing :

“The Windows Media Format Runtime is required in order to install this component. Installing the WMFR may require a system restart to complete the installation. Click OK to continue with the installation”

To get round this (but only in a test lab) you can do the following:

pkgmgr.exe /ip /m:”%windir%\servicing\Packages\Microsoft-Windows-Media-Format-Package~31bf3856ad364e35~amd64~~6.0.6001.18000.mum”

Taken from technet

Office Communications Server 2007 R2, OCS 2007 or LCS 2005 does not work correctly after you upgrade to Windows Server 2008 R2

Office Communications Server 2007 R2, OCS 2007 or LCS 2005 does not work correctly after you upgrade to Windows Server 2008 R2:
http://support.microsoft.com/default.aspx?scid=kb%3ben-us%3b982020

Looks like a rerun of the Forest Prep can help fix.