Why can't I call my shell script as a notifer?

I want to call a shell script as notifier, but I keep getting this error.   I can't seem to find an answer when I search for it.

Unable to test 'SDM-nerd-sms'.

Notifier SDM-nerd-sms test failed with code 254.
See server debug log for details.

The script is very simple.  It uses curl to send a message to a web server.  When I run the script from a standard shell, it works perfectly.  When I ask InterMapper to execute it, I get the error above.

Here is the Debug:

16:09:58 Notifier SDM-nerd-sms test failed with code 254 (Error 13 returned by operating system when attempting to execute probe.
Please check your command-line and any scripts it calls for errors.

Any idea?

Here is the script:

#!/bin/bash
SENDTO=mynamehere
MESSAGE=$(echo "$@" | sed -e 's/\ /+/g' | sed 's/[^a-zA-Z0-9+]//g')
curl -s "http://mywebsitehere/sms/send.php?to=$SENDTO&message=$MESSAGE"

Thanks!

Ahh, found the problem.  But really, why can't the error messages be a little bit more verbose?  For example, how about "permission denied, or can't execute.  Maybe something other than "Error 13."

Issue was that the InterMapper user did not have permission to execute the script.