I'll be mulling this over, I'm sure, I can't let a good problem like
this rest ;) So, hopefully sooner than later, it will get solved.
I figured out the problem. To recap, I was trying to use the shebang notation to specify that ruby should be used to execute the script. Common thing. however, I had a layer of indirection, the wrapper script I had placed around ruby to set an environment variable. When the system starts it up as an interpreter to run the script in question, I think it's a fundamentally different process from the command line invocation of the wrapper script. Basically, when the system fires up the shebang specified exectuble, I don't think any params get handed in, so in this case nothing happens with my exec line - the line that fires up ruby with the file itself as the param.