Make sure the names in the host file and those used to add hosts match exactly. The pvmd uses strcmp() to match names in the host file, so local names won't match fully qualified ones, e.g. thud is different than thud.cs.utk.edu.
Also, the master pvmd gets its name from gethostbyname() (like the hostname command) unless you change it with the -n command-line parameter. If this doesn't match a name in the host file, parameters for the master pvmd won't get set.