Camera#setLocation doesn't work as I wish

I use this code to move camera:

[java]

public void onAnalog(String name, float isPressed, float tpf)

{

Vector3f move = new Vector3f();

if (name.equals("Forward"))

move.z = -1;

if (name.equals("Back"))

move.z = 1;

if (name.equals("Right"))

move.x = 1;

if (name.equals("Left"))

move.x = -1;

cam.setLocation( cam.getLocation().add(move).mult(tpf * 200) );

}

[/java]



but when I press a key it moves camera only a little and then stops and pulsates.

What am I doing wrong?