There will be a line at the top of your aspx page that reads:
<%@ Register Assembly="AjaxControlToolkit"
Namespace="AjaxControlToolkit" TagPrefix="cc1" %>

Change it to:
<%@ Register Assembly="AjaxControlToolkit"
Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>

You'll also have to update the tags of any items you have already added
to the page.

To save having to do this for every single page, you can add the
following to your web.config file under the <controls> node:

<add tagPrefix="ajaxtoolkit" namespace="AjaxControlToolkit"
assembly="AjaxControlToolKit"/>

Kind Regards
Mick Walker

If it works don't bother quite much about it. Maybe the docs that you are
checking belongs to an older version of the toolkit (a lot of material is
based on the ATLAS beta version).

Good luck
  Braulio

/// ------------------------------
/// Braulio Diez
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/// http://www.tipsdotnet.com
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