Have you only been editing the text documents in the scenes folder?
Do you still have a text doc named startup and another named choicescript_stats?
I played around in choicescript for a bit and the bare minimum needed to open without errors is, within the scenes folder, to have a text doc named startup (it can be completely blank as long as the file is named startup, but it is the file you’ll need to put your *title, *author, *scene_list, and *create commands in) and in order for the stats screen not to show an error you have to have another text doc named choicescript_stats and have at least one *stat_chart command typed in there.
Maybe as a last resort you can redownload choicescript?