Well, I can't quite figure out your program, but I can give you some code to do it:
rem make a matrix so we can see that we're moving
make matrix 1,1000,1000,20,20
rem position the camera
position camera 500,10,0
do
rem checking if the mouse is at the zero position on the x axis and moving the camera
if mousex()=<1 then position camera camera position x(0)-0.1,camera position y(0),camera position z(0)
loop
Hope it helps!
When you need to move on the z axis and the other x direction, just check for where the mouse is, and use the "camera position [insert axis here](0)+[or -]0.1"!
Felthenra-Cat. Hiss your way to freedom.