Since the release of Arma 3 Beta every time they change anything and that's like every day to every other day nothing in home made missions will work without being reedited.
They are also making changes to the map itself and anything connected to a static object must be reconnected to that object to make the mission work right.
They have changed the names of guns, vehicles and other things that are in the game making the game think the items are no longer there and the missions will not load to let you edit them. If you can open the script in Notepad and remove the items that cause the error and save it back out sometimes it works, sometimes it doesn't.
I'm not going to upload any more ARMA 3 missions until they find some stable point where the missions I make will remain functional.