Acf gearbox error

[dvdvideo1234]

[acf] addons/acf/lua/entities/acf_gearbox.lua:826: Tried to use a NULL entity!
  1. GetPhysicsObject - [C]:-1
   2. CalcWheel - addons/acf/lua/entities/acf_gearbox.lua:826
    3. RPMCheckup - addons/acf_custommod/lua/entities/acf_gearbox_manual.lua:670
     4. Calc2 - addons/acf_custommod/lua/entities/acf_gearbox_manual.lua:591
      5. CalcRPM - addons/acf_custommod/lua/entities/acf_engine_maker.lua:996
       6. unknown - addons/acf_custommod/lua/entities/acf_engine_maker.lua:788 (x2)

[acf] addons/acf/lua/entities/acf_gearbox.lua:592: 'for' limit must be a number
  1. UpdateOverlayText - addons/acf/lua/entities/acf_gearbox.lua:592
   2. unknown - addons/acf/lua/entities/acf_gearbox.lua:670