I could not have tested the OOS issues myself, so I have to beleive what I am told.
Anyway, if you know any other OOS sources, please let me know
Regarding ranged attacks, you need to disable them on every unit, not just barbs. If removing them from barbs fixes OOS, that is not ranged attack that was the real problem...
The easiest way is to set iAirRange of all units to 0
Most have just 1, some have 2. You can do it using notepad or Orbis Editor if you can use it.
Also, 3 promotions increase it (iAirRangeChange) so should be changed too.
I will think of providing a MP fix with the next patch (disabling certain features to remove OOS).
@James009
Is your fix for a current patch? if not, it might need updating. I can't really check it ATM.