I found out about openRCT2 3 weeks ago and at that point I downloaded the current stable release. I can't find my loopy landscapes disk (no surprise, my parents bought my brother and I this game when it was released, 19 years is a long time to not lose something) so I have not installed the triple thrill pack. Could that be the issue?
edit: if I remember correctly, that file was there but I will verify when I'm home