For lack of a better idea, I would do this:
1. Go to Settings>Apps>All>Camera.. Force stop then clear cache and data for it.
2. The using root explorer or something similar drop this into /system/app (you might have to hit Mount RW on the top grey button), say yes when it asks to overwrite existing, then reboot right away. http://db.tt/mBHZdSYC
This is the camera apk from aokp b39. I've confirmed it works perfectly so if you follow those instructions you should be alright. Let me know