im using win xp sp2, 2gb ram so what is the prob? 

(Filename:  Line: -1)

NullReferenceException
  at (wrapper managed-to-native) UnityEngine.Component:GetComponentFastPath (System.Type,intptr)
  at UnityEngine.Component.GetComponent[Building] () [0x00000] in <filename unknown>:0 
  at FarmerAction.IsTargetNear (.Actionable Target) [0x00000] in <filename unknown>:0 
  at FarmerAction.DoAdd () [0x00000] in <filename unknown>:0 
  at FarmerStateAdding.UpdateState () [0x00000] in <filename unknown>:0 
  at Farmer.UpdateState () [0x00000] in <filename unknown>:0 
  at Farmer.Update () [0x00000] in <filename unknown>:0 
  at Worker.Update () [0x00000] in <filename unknown>:0 

that command is copy paste on output_log same error every time ill play 

even the clay, sand, sea sand, metal, ill still play