qstat can not be found on host with outdated debian versions. These hosts do not have GPU's installed.
all files named [0-9][0-9]* in /opt/SGE/local/scripts/{prolog,epilog,pe_prolog,pe_epilog}.d and in /usr/local/etc/gridengine/{prolog,epilog,pe_prolog,pe_epilog}.d will be executed.