Exception when dealing with method call (.net addon)

"Object reference not set to an instance of an object."

   at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.a(IDomType A_0)
   at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.GetExtensionMethods(IDomType contextType, String[] importedNamespaces, IDomType targetType, String name, DomBindingFlags flags)
   at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.a(DotNetLanguage A_0, DotNetContext A_1, IDomType A_2, IDomMember A_3, Int32 A_4, Boolean A_5)
   at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetProjectResolver.GetQuickInfo(DotNetLanguage language, DotNetContext context)
   at ActiproSoftware.SyntaxEditor.Addons.DotNet.Dom.DotNetSyntaxLanguage.a(DotNetLanguage A_0, SyntaxEditor A_1, Int32& A_2)
   at ActiproSoftware.SyntaxEditor.Addons.CSharp.CSharpSyntaxLanguage.OnSyntaxEditorViewMouseHover(SyntaxEditor syntaxEditor, EditorViewMouseEventArgs e)
   at ActiproSoftware.SyntaxEditor.SyntaxLanguage.a(SyntaxEditor A_0, EditorViewMouseEventArgs A_1)
   at ActiproSoftware.SyntaxEditor.SyntaxEditor.b(EditorViewMouseEventArgs A_0)
   at ActiproSoftware.SyntaxEditor.EditorView.OnMouseHover(MouseEventArgs e)
   at ActiproSoftware.WinUICore.UIElement.ActiproSoftware.WinUICore.IInputElement.RaiseMouseHoverEvent(MouseEventArgs e)
   at ActiproSoftware.WinUICore.UIControl.OnMouseHover(EventArgs e)
   at System.Windows.Forms.Control.WmMouseHover(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at ActiproSoftware.SyntaxEditor.SyntaxEditor.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 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 RhORMQuery.Pilot.UI.Program.Main() in C:\Progs\Righthand\RhORMQuery\RhORMQuery.Pilot.UI\Program.cs:line 22