If all you can see is sea then that usually means the camera has been created at 0,0,0 which is sea but it doesn't understand the next command.
This line looks odd
_cam cameraeffect ["internal", "white"]
Try this:-
; camera script
titlecut [" ","BLACK IN",3]
enableradio false
_cam = "camera" camcreate [0,0,0]
_cam cameraeffect ["internal", "back"]
_cam camsettarget fire
_cam camsetrelpos [2,2,2]
_cam camcommit 0
@camcommitted _cam
~8
titlecut ["","BLACK OUT",2]
~2
_cam cameraeffect ["terminate", "back"]
camdestroy _cam
enableRadio true
exit
When the mission is ready post it in the beta forum. There's a sticky at the top of that board with some tips.