This means that a function in the group library (libgpvm3.a) could not spawn a group server task. Tasks using group library functions must be able to communicate with this server. It is started automatically if one is not already running. The group server executable (pvmgs) normally resides in $PVM_ROOT/bin/$PVM_ARCH, which must be in the pvmd search path. If you change the path using the host file ep= option, make sure this directory is still included. The group server may be spawned on any host, so be sure one is installed and your path is set correctly everywhere.