I'm not familiar with these commands but I noticed you had some clitches in your script..
_cam is the name of the camera you create, which is cool, but you've confused the command and the camere name together.
_cam setBank 120
_camCommit 10
In my mind should be
_cam camsetBank 120
_cam camCommit 10
*cough* uhm.. same thing with the upper part of the script.
_cam = "camera" camCreate [4000,3000,10]
_cam settarget [4020,3020,10]
_cam setFov 0.1
_cam setBank 20 //Tried also decimal values
_cam camCommit 0
should be
_cam = "camera" camCreate [4000,3000,10]
_cam camsettarget [4020,3020,10]
_cam camsetFov 0.1
_cam camsetBank 20 //Tried also decimal values
_cam camCommit 0
Those are the ones I found, but I'm not an expert though.