My issue is that I have a blender file in which cameras and lamps do not move when I attempt to rotate them using the mouse. If I select the objects (in object mode), press R, and move the mouse in the viewport, the lamps and cameras don't respond; they remain in the same orientation as when I started, no matter how vigorously I try to move the mouse. The values in the information bar show that the mouse is communicating. If, however, I manually enter a new value for the amount of rotation in the properties shelf of the viewport, the camera moves to the new orientation.
On a new default Blender scene, the cameras and lamps do respond to commands to rotate and scale using the mouse. I've compared all of the settings I can think of, and don't see anything obvious that corrects the problem.
~.blend file is available.