Type 'Telerik.Charting.ChartSeries' does not have a public property named 'ChartSeries'

[John]

Hello forum members, i'm getting this error on an aspx page.  I am using it elsewhere, with the same assembly directives:

<%@ Register TagPrefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI, Version=2008.2.723.20, Culture=neutral, PublicKeyToken=121fae78165ba3d4" %>
<%@ Register TagPrefix="telerik" Namespace="Telerik.Charting" Assembly="Telerik.Charting, Version=2.0.3.0, Culture=neutral, PublicKeyToken=d14f3dcc8e3e8763" %>
<%@ Register assembly="Telerik.Web.UI, Version=2008.2.723.20, Culture=neutral, PublicKeyToken=121fae78165ba3d4" namespace="Telerik.Charting" tagprefix="telerik" %>
<%@ Register TagPrefix="ajaxtoolkit" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit, Version=1.0.10920.32880, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e" %>


any thoughts?