HMS Host activation on w2k3 R2

Hi,
I can't activate KMS Host on w2k3 R2 VL. I follow the "Hosting Key
Management Service Version 1.1 on Windows Server® 2003 SP1 and later
computers Step-By-Step Guide" and I'm stuck on step 3 - "3. Run the following
script to install your KMS key:
cscript C:\windows\system32\slmgr.vbs /ipk <KMS Key>"

all I got is:
"Error: 0xC004F050 The Software Licensing Service reported that the product
key is invalid"

I'm sure I'm using the proper KMS key. The server has been updated and
restarted. How can I activate the KMS Host on w2k3 R2?

greetings,
Olo

For Office 2010 activations an Office 2010 KMS Host is needed. It can be
downloaded from Volume Licensing Service Center.