A couple of things pop to mind:
1) try running scriptutil -l and see if your sensor shows up in the list.
2) look at the header in the script. scriptutil works by parsing the comments at the top each script. if you are not using the format that is expected, then this could be the cause (see another sensor for an example).
3) what is the name of the sensor? scriptutil will first look for a sensor with an extenstion equal to the OS of the target machine (e.g., ). Some people make the mistake of appending .sh or .nsh to the sensor file name. I believe scriptutil will have problems finding a match if this is the case.
Lastly, can you post the sensor here to help us debug your problem?