Created Unassigned: Not Working in Medium Trust Hosting [27799]

This might be an old issue, and I dont know if it is already solved, this is the stack trace:

[ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.]
System.Reflection.RuntimeModule.GetTypes(RuntimeModule module) +0
System.Reflection.RuntimeModule.GetTypes() +4
System.Reflection.Assembly.GetTypes() +61
AjaxControlToolkit.ToolkitScriptManagerConfig..cctor() +68

[TypeInitializationException: The type initializer for 'AjaxControlToolkit.ToolkitScriptManagerConfig' threw an exception.]
AjaxControlToolkit.ToolkitScriptManager..ctor() +62
ASP.webmaster_thediscourse_aspx.__BuildControlajaxscm() +26
ASP.webmaster_thediscourse_aspx.__BuildControlContent4(Control __ctrl) +92
System.Web.UI.CompiledTemplateBuilder.InstantiateIn(Control container) +10
System.Web.UI.MasterPage.InstantiateInContentPlaceHolder(Control contentPlaceHolder, ITemplate template) +88
ASP.webmaster_webmaster_master.__BuildControlCPHMain() +116
ASP.webmaster_webmaster_master.__BuildControlform1() +377
ASP.webmaster_webmaster_master.__BuildControlTree(webmaster_webmaster_master __ctrl) +183
ASP.webmaster_webmaster_master.FrameworkInitialize() +46
System.Web.UI.UserControl.InitializeAsUserControlInternal() +32
System.Web.UI.MasterPage.CreateMaster(TemplateControl owner, HttpContext context, VirtualPath masterPageFile, IDictionary contentTemplateCollection) +886
System.Web.UI.Page.get_Master() +54
System.Web.UI.Page.ApplyMasterPage() +14
System.Web.UI.Page.PerformPreInit() +45
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +335