POPupcontrolextender error in IE8

I'm trying to use the 4GuysFromRolla post (http://www.4guysfromrolla.com/articles/071107-1.aspx).  Works great in IE9, SAF 5.1.7, FF19, CHR 26, but gives the "A script on this page is causing IE to run slowly...." error and it quits working.  Any help?  Here's the pertinent code:

<asp:GridView ID="dgList" runat="server" DataSourceID="sourceDirectory" AutoGenerateColumns="false" DataKeyNames="dir_pk"  ><Columns><asp:BoundField DataField="dir_pk" HeaderText="dir_pk" Visible="false" /><asp:TemplateField HeaderText="Details"><ItemTemplate><asp:Image ID="Image1" runat="server" ImageUrl="~/images/icon-previewSm.gif" BorderWidth="0" /><ajaxToolkit:PopupControlExtender ID="PopupControlExtender1"
   runat="server"
   DynamicServiceMethod="GetDynamicContent"
   DynamicContextKey='<%# Eval("dir_pk") %>'
   DynamicControlID="Panel1"
   TargetControlID="Image1"
   PopupControlID="Panel1"
   Position="right"
 /></ItemTemplate></asp:TemplateField><System.Web.Services.WebMethodAttribute()> <System.Web.Script.Services.ScriptMethodAttribute()> Public Shared Function GetDynamicContent(contextKey As String) As System.String
        Dim sTemp As New StringBuilder
        Dim strConn As String = ConfigurationManager.ConnectionStrings("strConn").ConnectionString
        Dim cn As New Data.SqlClient.SqlConnection(strConn)
        Dim cmd As Data.SqlClient.SqlCommand
        Dim strSql As String = "SELECT blah blah FROM  dbo.tblDirectory AS d where d.dir_pk=" & contextKey.ToString
        cmd = New Data.SqlClient.SqlCommand(strSql, cn)
        'lblMsg.Text = strSql
        cn.Open()
        Dim dr As Data.SqlClient.SqlDataReader = cmd.ExecuteReader
        If dr.HasRows Then
            sTemp.Append("<table><tr><td align=>")
            While dr.Read
                sTemp.Append("<br />" & dr("person").ToString)
               	sTemp.Append("<br /><br />" & dr("bio").ToString)
                sTemp.Append("</td></tr></table>")
            End While
        Else
            sTemp.Append("<i>No details found.</i>")
        End If
        dr.Close()
        cn.Close()
        Return sTemp.ToString()
End Function

Protected Sub dgList_RowDataBound(sender As Object, e As GridViewRowEventArgs) Handles dgList.RowDataBound
        If e.Row.RowType = DataControlRowType.DataRow Then
            Dim pce As AjaxControlToolkit.PopupControlExtender = CType(e.Row.FindControl("PopupControlExtender1"), AjaxControlToolkit.PopupControlExtender)
            Dim behaviorID As String = String.Concat("pce", e.Row.RowIndex)
            pce.BehaviorID = behaviorID
            Dim i As Image = CType(e.Row.Cells(1).FindControl("Image1"), Image)
            i.Attributes.Add("onmouseover", String.Format("$find('{0}').showPopup();", behaviorID))
            i.Attributes.Add("onmouseout", String.Format("$find('{0}').hidePopup();", behaviorID))
        End If
End Sub