Have you tried older version of OFS? 1.2.0 was a big change so there might be things that won’t work on some platforms, you might want to try something prior to that, maybe 1.1.9 will work: https://github.com/gagax1234/OpenFunscripter/releases
There was similar problem when OFS showed up first time:
https://discuss.eroscripts.com/t/openfunscripter-another-scripting-tool-1-1-9-release/4457/22