Try to manually start the vmserverdWin32.exe in your installation location. what is the version are you using.
This just happened to me with VMWare Server 2.
In my case the hostd logs (in UserFolder\Application Data\Vmware\Vmware server) pointed to a problem with the config.xml in the hostd folder (under the same path). Te re-install did not work for me as it did not for the oroginal poster because this xml file or the whole hostd directory did not get updated.
I have re-named the hostd directory and re-installed again; the new hostd directory was created. Problem solved.
P.S. the hostd logs diplayed the same output one would get by running Host Agent executable comman at the command prompt.