Missing orphaned DFS Namespace server

I have a failed namespace server that is not listed in AD and not found in ADSI but is showing in DFS management as a DFS namespace server. I cannot delete it and get the warning that the namespace server cannot be forcibly removed.

What is the correct cmd line syntax to run?

dfsutil /unmapftroot /root:\\hdh.local\DFS /server:\\missingserver

When I run it I get this

USAGE:

Dfsutil /UnmapFtRoot deletes DFS references to an obsolete
domain based root replica. This is a special problem repair
command and should not be confused with commands such as /RemFtRoot.

Usage:
dfsutil /UnmapFtRoot /Root:<\\Domain\RootShare>
        /Server:<RootTargetServer> /Share:<RootTargetShare>

    /Root:<DfsPath> - DFS domain root to operate on.
    /Server:<RootTargetServer> - Name of the root target server to unmap.
                      Should be exactly as it appears in Dfs replica info.
    /Share:<RootTargetShare> - Name of the root replica share to unmap

    e.g: dfsutil /UnmapFtRoot /Root:\\DocDomain\DocRoot
              /Server:DocRootServ2 /Share:DocRoot2

            dfsutil /UnmapFtRoot /Root:\\DocDomain\DocRoot
              /Server:DocRootServ2.DocDomain.mycomp.com /Share:DocRoot2

This is the suggested MS syntax from http://technet.microsoft.com/en-us/library/cc776211(v=ws.10).aspx  and is not clear what I need to substitute.

dfsutil /unmapftroot /root:\\ex.com\salesdata /server:\\mainshare1

dfsutil /unmapftroot /root:\\domain\share /server:failedserver /share:share

It would be nice to have a little explanation as to what each entry designates and I haven't found one!

Thanks, Charlie