OK, I just uploaded a new file that should do the trick (see page 1).
Basically, the compiler was converting two of the variables into symbols during initialization ---- it had never done this before, so I'm not sure why it started doing it now. But the symbols broke the code on the initialization passage and then caused other errors where other variables hadn't been properly initialized. I changed the names of the variables and now everything seems to work fine --- no errors on either Chrome or Edge.