How do I fix the 'Invalid Expressions' errors

I was working on a project today and I copied a layout and eventsheet from an old project. When I went to preview it I got a blank screen so I saved, quit, and reloaded it. I now get this error.

It tells me there are invalid expressions and I need to fix them before using the project. The problem is I can't open the project to fix the offending expressions.

I tried changing the .c3p to .zip and editing the lines by hand but then I get a "Failed to open project. Check it is a valid Construct 3 single file (.c3p) project" error.

Is there any way I can recover the project?

For anyone who has the same problem, I solved it this way:

1. Rename the file from .c3p to .zip
2. Un-zip the file to a folder
3. Change the offending lines in the eventSheet.json file in a text editor
4. Open as a local project folder instead of a converting back to a single file project.