Mono is being derpy help

I keep getting this error every time I try to open up a script:

System.NullReferenceException: Object reference not set to an instance of an object. at MonoDevelop.Ide.Gui.Components.ExtensibleTreeView.GetBuilderChain(Type type) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Components\ExtensibleTreeView.cs:line 1364 at MonoDevelop.Ide.Gui.Components.ExtensibleTreeView.TreeBuilder.AddChild(Object dataObject, Boolean moveToChild) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Components\TreeBuilder.cs:line 210 at MonoDevelop.Ide.Gui.Components.ExtensibleTreeView.AddChild(Object nodeObject) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Components\ExtensibleTreeView.cs:line 530 at MonoDevelop.Ide.Gui.Pads.SolutionPad.OnOpenWorkspace(Object sender, WorkspaceItemEventArgs e) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Pads\SolutionPad.cs:line 56 at MonoDevelop.Ide.RootWorkspace.NotifyItemAddedGui(WorkspaceItem item, Boolean reloading) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide\RootWorkspace.cs:line 1091 at MonoDevelop.Ide.RootWorkspace.<>c_DisplayClass25.b_22(Object param0, EventArgs param1) in c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide\RootWorkspace.cs:line 1063 at Gtk.Application.InvokeCB.Invoke() at GLib.Timeout.TimeoutProxy.Handler()