If I run it from a telnet prompt it will add t the hijack menu and I can run it.

If I run it from the config.ini then it doesn't appear in hijack and I see no mention of it in the serial output.
My config.ini shows:

;@EXEC=/usr/local/bin/empeg-wideband

or have tried:
;@EXEC_ONCE=/usr/local/bin/empeg-wideband

The paths are correct and it's 755 for permissions on the file.
But telnet in again and I can run it !!