Created Issue: Download reference c:\users\Stephen\Downloads\ajax... ??? [27123]

Where do I change this. Just downloaded, and added to TOOLBOX like it said, and now says looking for some guys setup structure... will figure this out, but where would this be...
thank you
frank



[NullReferenceException: Object reference not set to an instance of an object.]
AjaxControlToolkit.MaskedEditValidator.OnPreRender(EventArgs e) in C:\Users\Stephen\Downloads\ajaxcontroltoolkit-a497357d78ce\AjaxControlToolkit_a497357d78ce\Server\AjaxControlToolkit\MaskedEdit\MaskedEditValidator.cs:360
System.Web.UI.Control.PreRenderRecursiveInternal() +103
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496