Adding more than one SelectParameter in ObjectDataSource...

Hi, I would appreciate your help. I have this piece of code from a book, ASP 3.5, Unleashed. I read the chapter and tried the example. it works, but when I am trying to add more than one parameter, it fails. Currently, it works with one para, but I am not able to make it run with two or more parameter. Thanks for your help in advance Aspx Code ----------------- <form id="form1" runat="server"> <div> <strong><span style="font-size: 24pt">ObjectDataSource: Filtering data using <br /> Parameters<br /> </span></strong> <br /> <asp:TextBox ID="txtSearchCriteria" runat="server"></asp:TextBox> <asp:TextBox ID="txtCountry" runat="server" Width="75px"></asp:TextBox> <asp:TextBox ID="txtState" runat="server" Width="92px"></asp:TextBox> <asp:Button ID="btnSearch" runat="server ...