Finale and .mus file

[Benjamin]

Greetings. I've been having some slight issues with Finale (version 26), so whenever I like open a music file (.mus) from this site these messages pop up (seen here: https://imgur.com/a/8wLzjRa). How can I fix this? Thank you in advance.

And another thing, do y'all think that you could post/link me up to some vst soundfonts?