Oh, the optional sensor you got is a different model than the original, Omnivision ov7725 instead of originally an ov9650. To use it, you need to configure the JeVois software as explained here:
http://jevois.org/doc/Sensors.html
Basically, you just need to write a file called "sensor" in the boot partition of the microSD and in there write a single word: ov7725
Then the camera will attempt to detect and use that sensor when it starts up.