The problem lies with the "code" in your callback. Callback code is literally a string interpreted and executed by the built-in interpreter selected by the "language" field. Since a job you submit is actually a data object submitted to the Supervisor, it doesn't share any code space with script that submitted it, and consequently you can't reference it.
If your socket script is a little too complicated to pack into a string without some serious debugging and maintenance grief, I'd recommend you save it out as a script and call it externally from your callback. (You can use the os.system() call).