@ysc ,
I am sorry, the camera ID vs slot ID may be a bit confusing when you first start playing with camera configurations.
In your case you only have one camera plugged into Camera Hardware Slot 2, (so you use the sensormodule with index 2), but once the cameras are detected by the system, they are assigned with camera ids which start with 0. So in your configuration file, you need to set camera_id to 0 and it should be called camera_id, not camId. -- you actually have both of those, so please remove camId and camId2 entries, and just set camera_id to 0.
You also have some duplicate (incorrectly named) parameters such as pre_width and pre_height -- the correct ones are preview_width and preview_height, which are also there. I think you probably got those from the information that camera server prints out when it starts, which actually does not use correct parameter names, such as camId and pre_width, etc... We should fix that..
Alex