If you have a KMS server running, newly installed servers will automatically activate. However, you can also manually activate your server by entering the command slmgr.vbs /ato
In my case, I recently installed a Windows 2008 SP2 server, but couldn’t get the machine activated. Everytime I ran the command slmgr.vbs /ato, the following error returned:
Run ‘slui.exe 0x2a 0x80004FE2F’ to display the error text
When running this slui.exe command, the following message displayed:
… yep, a pretty nothing saying message indeed! :-)
To resolve this problem, I needed to install KB968912. This update is needed for a successful registration to the KMS server. This update may also be needed on Windows 7, Windows Server 2008 R2 and Windows Vista. The update requires a reboot after installation.