请帮忙分析下。这个代码是什么错误？

jay2012

ArgumentOutOfRangeException: Argument is out of range.
Parameter name: index
  at System.Collections.Generic.List`1[DawnOfMan.ResourceType].get_Item (Int32 index) [0x00000] in <filename unknown>:0
  at DawnOfMan.AttackManager.launchRaiderAttack (Int32 raiderCount) [0x00000] in <filename unknown>:0
  at DawnOfMan.AttackManager.launchAttack () [0x00000] in <filename unknown>:0
  at DawnOfMan.AttackManager.tick (Single timeStep) [0x00000] in <filename unknown>:0
  at DawnOfMan.GameStateGame.fixedUpdate (Single timeStep, Int32 frameIndex) [0x00000] in <filename unknown>:0
  at DawnOfMan.GameManager.fixedUpdate (Single timeStep) [0x00000] in <filename unknown>:0
  at DawnOfMan.GameBehaviour.FixedUpdate () [0x00000] in <filename unknown>:0