1. #include <weapon-config> before any other script

2. Replace OnPlayerGiveDamage and OnPlayerTakeDamage with just one callback:

   public OnPlayerDamage(&playerid, &Float:amount, &issuerid, &weapon, &bodypart)

3. Add config functions in OnGameModeInit (or any other places, they can be called at any time). Recommended:

public OnGameModeInit() {
    SetVehiclePassengerDamage(true);
    SetDisableSyncBugs(true);
}