Anyone knows what this is?

[Pyrogamer94]

Root level exception in Update(): System.NullReferenceException: Object reference not set to an instance of an object
  at Verse.KeyBindingDef.get_JustPressed () [0x00005] in <4b53ac099a7e43a0bd38f6db4241a7ad>:0
  at Verse.ScreenshotTaker.Update () [0x00008] in <4b53ac099a7e43a0bd38f6db4241a7ad>:0
  at Verse.UIRoot.UIRootUpdate () [0x00000] in <4b53ac099a7e43a0bd38f6db4241a7ad>:0
  at Verse.UIRoot_Entry.UIRootUpdate () [0x00000] in <4b53ac099a7e43a0bd38f6db4241a7ad>:0
  at (wrapper dynamic-method) Verse.Root.Verse.Root.Update_Patch1(Verse.Root)
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) Verse.Log:Verse.Log.Error_Patch1 (string)
(wrapper dynamic-method) Verse.Root:Verse.Root.Update_Patch1 (Verse.Root)
Verse.Root_Entry:Update ()