Export Dataset to Excel

I use the following script to export dataset to excel

Public Class DataSetToExcel

  Public Shared Sub Convert(ByVal ds As DataSet, ByVal response As HttpResponse)
    'first let's clean up the response.object
    response.Clear()
    response.Charset = ""
    'set the response mime type for excel
    response.ContentType = "application/vnd.ms-excel"
    'create a string writer
    Dim stringWrite As New System.IO.StringWriter
    'create an htmltextwriter which uses the stringwriter
    Dim htmlWrite As New System.Web.UI.HtmlTextWriter(stringWrite)
    'instantiate a datagrid
    Dim dg As New DataGrid
    'set the datagrid datasource to the dataset passed in
    dg.DataSource = ds.Tables(0)
    'bind the datagrid
    dg.DataBind()
    'tell the datagrid to render itself to our htmltextwriter
    dg.RenderControl(htmlWrite)
    'all that's left is to output the html
    response.Write(stringWrite.ToString)
    response.End()
  End Sub
End Class

It has been working fine except now that I move the script to a new SharePoint server, it stops working.  Instead of exporting the dataset to an excel, it displays the XML on the screen.  Help.