win32ole with 'VirtualServer.Application'?

[jfc]

require 'win32ole'
vs=3DWIN32OLE.new('VirtualServer.Application')
vm =3D vs.FindVirtualMachine("Windows 2000 Server")

the error:
WIN32OLERuntimeError: FindVirtualMachine
OLE error code:80070542 in <Unknown>
<No Description>
HRESULT error code:0x80020009
Exception occurred.
from (irb):22:in `method_missing'
from (irb):22


what is wrong?

Thank