OK, this problems very easy to solve.
To explain with more detail than an answer:
Basically, it looks like you have "cut" out of the cutscene and destroyed the camera.
The problem is, you need to "cut" back in (ie. to the game). I made the same mistake countless times when I was starting out as well.
The answer:
You need a
titlecut [" ","WHITE IN",2]
inbetween camDestroy _cam and exit
You can also "BLACK IN" - depending on your preference.