Whenever I go to active camera view and try to rotate to look around, AE just makes a "ding" noise and refuses to let me uses the camera tool to move the view.
I know it must be because I have something selected, but I've tried to deselect everything, to re-add elements, etc.
You have to have 3D layers and a Camera. Add a camera and make at least one of your layers 3D and you'll be able to move around.
ah, i didn't realize i'd turned my camera off! thank you!