Ajax Accordion control is not working.

Question

Thank you for all the replies. This is my source code..

asp:Accordion ID="sample_accordion1" 
                CssClass="accordion" 
                HeaderCssClass="accordionHeader" 
                HeaderSelectedCssClass="accordionHeaderSelected"
                ContentCssClass="accordionContent"
                runat="server" 
                SelectedIndex="0"
                FramesPerSecond="30"
                TransitionDuration="200"
                AutoSize="None">
                <Panes>
                    <asp:AccordionPane ID="AccordionPane1" runat="server">
                    <Header>Accordion 1</Header>
                    <Content>
                      Some text..................
                    </Content>
                    </asp:AccordionPane>
                    <asp:AccordionPane ID="AccordionPane2" runat="server">
                    <Header>Accordion 2</Header>
                    <Content>
                       Some text here......................
                    </Content>
                    </asp:AccordionPane>
                    <asp:AccordionPane ID="AccordionPane3" runat="server">
                    <Header>Accordion 3</Header>
                    <Content>
                        Some text here.................
                     </Content>
                     </asp:AccordionPane>
                     </Panes>
                    </asp:Accordion>

And this code is not working in my scenerio. Only one accordianPane is open(1st one). And I couldn't find any errors...Is this a problem related with my ajax toolkit installation ? I am using VS2008. And Ajax toolkit version 3.5. I am just biginner in ajax controls. :(