Currently, only MPI parallel binaries are included in NWChem. Please compile and include a sequential version as well. One is available, judging from http://www.nwchem-sw.org/index.php/Release65:Running#Sequential_execution
Ah, no matter, seems like sequential binaries aren't supported http://www.nwchem-sw.org/index.php/Special:AWCforum/st/id1138/Nwchem-src-2014-01-28%3A_ARMCI_NET....html