Clark:
Thanks for your help!
It could be useful if you add an error message print from vs_exe if it is not run through the wrapper script vs.
In similar situations at my office when I have wrapper scripts I have the tool that is only supposed to be run from the wrapper output an error message if not run through the wrapper to minimize the wasted time.
The reason I went to vs_exe instead of vs was that I saw it in the "ps -ef" output. I shouldn't have done that. An error message like this would help someone who tries that.