First, thank you for answering so fast, I was surprised it was even alive this forum. So I checked the 'show required addons' and me and my friend have all the mods needed. There was one thing missing, but then there was an option to 'force load' it so I did it. Then we tested again, but now we've got the same message with this time 1 or 2 mods less (see previous message photo). If I can remember good, it was the il76td mod and one more thing that disappeared this time. I really read your message over and over to fix it but I can't solve it.
Yes I can edit the mission, Do I need to unload all the mods that I don't use in my scenario?