Please check that your libsm64-g64 package is up to date. To do this, look in your console for something like "Loaded G64 binary module! (Package version x.x.x)". The version number should match the version here: https://github.com/ckosmic/g64/releases/latest.
Alternatively, you can just check the console to see if it says your libsm64-g64 package is outdated.
If it IS in fact outdated, please turn on auto-updates in the G64 settings and leave/rejoin the map.
If you're still getting errors, you have to tell me what they are or else I can't fix it.