I have the same problem with the camera. I thought that it has to do something with the ROM because I have MIUI on my THL W200.
It also gives the error most of the time. Sometimes even after few restarts it still does not work. Sometimes it gives the green image only and it is possible to take photos blindly, which is not very helpful. I will try the methods described in this post tonight and post my experience soon.
Good luck everybody!