Server Manager in Windows Server 2008 is completely different from it's previous versions of Windows. Initial Configuration Tasks (ICT) and Server Manager query the registry entry described below to open the list of OEM Extensions.
When ICT and Server Manager starts, they query the registry entry: OEMExtensionXMLFilePath at the following registry location:
The OEMExtensionXMLFilePath contains the name of XML file which contains the OEM Extension path and link. If Server Manager fails to query the OEM Extensions then always check the above registry entry to make sure the path to the XML file is correct.