Incorrect call order of BeginMark/EndMark method.You call it like BeginMark(A), BeginMark(B), EndMark(B), EndMark(A) But you can't call it like BeginMark(A), BeginMark(B), EndMark(A), EndMark(B).
   at PerformanceUtility.GameDebugTools.TimeRuler.EndMark(Int32 barIndex, String markerName)
   at ZombieBlocks.NetworkedGameplayScreen.Draw3DSceneNew(GameTime gameTime, Int32 playerIndex, LocalPlayerSession player)
   at ZombieBlocks.NetworkedGameplayScreen.Draw(GameTime gameTime)
   at GameStateManagement.ScreenManager.Draw(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.Draw(GameTime gameTime)
   at ZombieBlocks.ZombieGame.Draw(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.DrawFrame()
   at Microsoft.Xna.Framework.Game.Tick()
   at Microsoft.Xna.Framework.Game.HostIdle(Object sender, EventArgs e)
   at Microsoft.Xna.Framework.GameHost.OnIdle()
   at Microsoft.Xna.Framework.WindowsGameHost.RunOneFrame()
   at Microsoft.Xna.Framework.WindowsGameHost.ApplicationIdle(Object sender, EventArgs e)
   at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FDoIdle(Int32 grfidlef)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at Microsoft.Xna.Framework.WindowsGameHost.Run()
   at Microsoft.Xna.Framework.Game.RunGame(Boolean useBlockingRun)
   at ZombieBlocks.Program.Main(String[] args)