Mfixgui error when open the mfix-20.3.1

[Cifer]

I downloaded a case from the internet, which was created using mfix-20.3.1 and modified the source code during calculation. However, when I also replaced the source code of mfix-20.3.1 and opened, It was prompted with the following error:

it is also not calculated. how should solve this problem?

[cgw]

This looks like a duplicate of Mfix.20.3.1 can not open