On some Pi camera modules the sunny connector might be loose enough to partially or completely disconnect during installation of the camera into the Spi-Box case.
When mounting the camera in place try not to jar the module too much. Ease it into the clips rather than snapping it in place. If this still does not solve the problem remove one of the camera clip mounting extrusions (by simply snapping it off) and rely on the provided screws to keep the camera in place.
The trim controls on the PIR set the sensitivity of the PIR and the speed at which the sensor resets. To identify which control is which on the PIR that you have purchased a good guide is described here including code sample for measuring the affect of changing them.