Hi,
WHS 2011 is not on the supported list What are the minimum system/hardware requirements? That does not mean it won’t run, but it’s not supported “out of the box”. I know some people are running Roon on MS Server 2012 (also not supported) maybe one of those chaps might be able to help.
There are a few topics on WHS 2011 like this one Running RoonServer on a WHS 2011 System? that might shed more light.