I brought the Fujifilm Instax Mini 8 a few days ago, and loaded the brand new (opened only when loaded) film into the camera in a really dark room (no direct light and no lights turned on). The first shot came off fine but since then every shot is completely underexposed. I've tried indoor and outdoor with both correct (as shown) exposure and moving the exposure a stop. The camera hasn't been dropped and the batteries are brand new. What could be causing the problem?

Cameras - FUJIFILM - instax mini 7 Digital Camera