NullReferenceException multiple errors received

Have gotten this error a couple of games when clicking on things to try and turn buildings on and off, a slow process, but I know they're working on that.  Anyway, found the error inn a log file.  Here is a paste of one of them.

 

NullReferenceException: Object reference not set to an instance of an object
  at HUDInfoBuilder.buildToggleOffInfo () [0x00000] in <filename unknown>:0

  at HUDInfoBuilder.guiGetObjectCostInfo () [0x00000] in <filename unknown>:0

  at HUDInfoBuilder.buildGameMouseover () [0x00000] in <filename unknown>:0

  at HUDListener.UpdateUI () [0x00000] in <filename unknown>:0

  at HUDListener.Update () [0x00000] in <filename unknown>:0