Hi bro,
We expreienced this error messages to.
The whole car spawn system was destroyed(car, heli crash)
After long hours of research, I realized that typing this line into globals.xml would stop spawning this error. I don't know its a solution or not, and don't know the variable is exist or not, but it works for us. Worth a try.
<var name="CarMaxCount" type="0" value="100"/> just quessed from zombiemaxcount variable.
This fixed the error for us but the spawners not working :(