A pretty bad problem.

[Nusua]

Alright so I set it so that when Object comes on collision with door, the game goes to the next screen. It was working for a while, but then my object touched the door and the test run closed down! What do I do?

[SoftWarewolf]

if the game closes on a "next frame" action, its possible you are on the last frame of the game.
the safest way is to use the "jump to frame" action instead

[Jacob]

Click run application instead of run frame.

[Shawn]

Click run application instead of run frame.

That could very well be the problem. If you run the frame only, any event that switches frames will close the test run down. You need to run the application not frame if you want to test multiple frames.

[Jacob]

It happens to me alot. Even as an "experienced" programmer I miss the button alot.