I just bought a used tamron 17-50 non-vc about 2 weeks ago. it was barely used and looked almost brand new. just today while taking pictures, an "err 01 - faulty connection between camera and lens, try cleaning lens contacts" message popped up. the camera turns on and everything works fine until i press the shutter and i get the message. all my other lenses work fine on my 60d. anyone know what could be causing this??