RCT3 Custom Coasters?

Hey I downloaded a coaster from Rct3 coaster exchange on atari.com. Where do i put it? Last time i put it in my doents/RCT3/ Coasters and when i tried to play, i got the error message 'Roller Coaster Tycoon 3 has stopped working'. But then when i deleted it, the game worked fine. What could be the problem?