No problem, thanks for trying to help me !
The thing is that we both have the same game, the same LanFix but whenever we're both on LanFix it crashes when we launch the game (with every map)

This is a known issue with T4M, confirmed does not work with a LanFix. This problem has persisted for years and no-one that I'm aware of has found a solution. If you do find a solution please let me know, would love to play t4m maps with my buddy!

Also, great map!