RCT3 Plus is installed. I used to use Gold before I got Platinum, so what do I do? Should I uninstall RCT3 then reinstall it? I'd like to have Wild! installed, so please help. Thanks!

I would personally go for an uninstall first, then install the new one.

Okay, I tried that, but I'm now having trouble installing. It seems to get to La La Land, then there's an error and it quits. It's happened a few times now..

There could be something corrupted or the game may be dirty and/or scratched.