Job sometimes works and sometimes fails

Sometimes this can be caused by problems with a particular node -- either a misconfiguration, or a temporary problem such as memory pressure from jobs with incorrect memory specifications. Check your job log file and see if the IP address on the "Job executing on host:" line is the same for all the failed jobs. If so, you should email linghelp so the situation can be fixed. As a temporary fix, you can avoid the problematic node by excluding it from your requirements, e.g.:

Requirements = ( Machine != "patas-n1.ling.washington.edu" )