The variable name '@Param' has already been declared
<p>I'm geting the following error message for given code when user clicks on search button more than two times. Could some one please help what i'm doing wrong.</p>

<blockquote>
  <p>The variable name '@Param' has already
  been declared. Variable names must be
  unique within a query batch or stored
  procedure.</p>
</blockquote>

<pre><code>protected void btnSearch_Click(object sender, EventArgs e)
{
    DS.SelectCommand = 
      "SELECT ReportName, ReportType, 
       FROM Table 
       WHERE ReportName LIKE @param 
       ORDER BY ReportType Desc";
   DS.SelectParameters.Add("Param", searchTxtBox.Text.Replace("'", "''"));
   DS.DataBind();
   ListView1.DataBind();               
}
</code></pre>
