Infrasgistic Tab not working

I am using Infrasgistic Tab controls but when i click on a different tab it doesnt change (select the clicked tab).... Below is the code for tab:


<igtab:UltraWebTab ID="UltraWebTab1" runat="server" BorderColor="Gray" BorderStyle="Solid"
            BorderWidth="1px" Height="432px" Width="888px" AutoPostBack="True" AsyncMode="On">
            <RoundedImage FillStyle="LeftMergedWithCenter" NormalImage="ig_tab_lightb1.gif" SelectedImage="ig_tab_lightb2.gif" />
            <DefaultTabStyle BackColor="WhiteSmoke" Height="20px">
            </DefaultTabStyle>
 &nb ...