A few days ago I finally finished installing the 'PEP Europa Park Addon Part 2' and was glad when it had finished. However, when I click on one of the coasters in-game rct3 crashes. I read the pdf and followed all the instructions but it still does this. Any Help?

You may need to install the coaster again. Sometimes it just happens at times. If it was a custom track did you download the custom track? Also, make sure there aren't any read me files in the file you installed. I may not be 100% right on this, but that is what I would check if I was using the same park.