Apparently, this JS Builder tool gives no indication when it fails, other than to produce bad output.
It is not compressing or obfuscating my scripts, and I wind up with the following in my directory:
11/10/2011 04:54 PM 733,798 sjs-all-debug.js
11/10/2011 04:54 PM 733,665 sjs-all.js
11/10/2011 04:54 PM 733,665 sjs-all.js-temp-707842769255.8569