Custom Campaign Start Up Problems

every time I click the button to start a map in the campaign all that happes is the screen goes black for a moment then goes right back to the campaign map selection screen again, how do I fix it so that the map will start

Update your Warcraft III.

I have the latest version and it still does that

Campaign may be corrupt, either due to faulty download, update, or something else.

I just started it today and the other buttons work fine

Map may be corrupt, or no longer at that file path.

maybe it's a problem with the map?