Are you using a Windows KMShost, for co-hosting Office KMShost?
Have you installed the Office2010 VLpack (update/patch), and installed/added the Office2010 KMShost product key on that host?
on the Office2010 KMShost, you can display all current KMShost licensing status information; (or pipe into a text file like this)
[elevated/admin console CMD prompt]
c:\windows\system32>cscript slmgr.vbs /dlv all > c:\windows\temp\slmout.txt
Does the output show the correctly licensed and activated Office2010 KMShost feature?
reference:
http://social.technet.microsoft.com/wiki/contents/articles/22510.volume-activation-kms-mak-adba-avma.aspx
Don [doesn't work for MSFT, and they're probably glad about that ;]