It sounds as if the CPL app couldn't write the config file (I guess the 'Apply' button doesn't even get disabled after you press it).
Aren't you running it from a folder under C:\Program Files\…?
I remember reading reports somewhere complaining the about the same problem, and it turned out that the CPL had to be run in Administrator mode otherwise it didn't have the right to write files.

Anyway, could you attach a debug log coming from the CPL, plz?

That's right, the Apply button doesn't get disabled after I press it.

I am running the game from C:\Program Files(x86)\Bullfrog\SimCoaster

I'm not sure what you mean by CPL. Where would I find this debug log, or is it something that's auto generated? (Also, when you say the CPL needs to run in Admin mode, are you talking about right clicking on the dgVoodoo launcher and running that in admin mode?)

Found out what you meant by CPL. I ran it in administrator mode and that fixed the problem. Thanks for your help!

Better install old games to other locations, e.g. D:\games. Windows vista and later introduced strict permission for Program files folder and sub-folders.