make sure that the prd_pre_to_post.sh shell script are uisng any ENV variable or not. if the script used any global variable you have to menstion in the script as well
one more things that the shell script (prd_pre_to_post.sh) is avalilabe or not in the spcefied directory (Path). if the script is availabe in the spcecified DIR try to execute by manually whethere its working or not?