Could not load type

Hey, guys.  I hope everyone is having a great day.  I am encountering a problem and I think I probably missed a simple step, but I have Ajax-ed in a while, so I can't remember.

I have a file upload control:

<ajaxtoolkit:AjaxFileUpload ID="AjaxFileUpload1" runat="server" />

I have this in my Web.config:

<system.web><httpHandlers><add verb="*" path="AjaxFileUploadHandler.axd"
            type="AjaxControlToolkit.AjaxFileUploadHandler, 
            AjaxControlToolkit"/></httpHandlers><pages><controls><add tagPrefix="ajaxtoolkit" namespace="AjaxControlToolkit" assembly="AjaxControlToolKit"/></controls></pages></system.web>

When I try to load my page, I'm told, "Could not load type 'AjaxControlToolkit.AjaxFileUploadHandler' from assembly 'AjaxControlToolkit'.".  

What simple thing have I missed?

Thanks in advance!