Microsoft JScript runtime error: Sys.InvalidOperationException: Two components with the same id

Hi ,

I was modifying code to show products based on Product Specification selected & want this feature to be implemented with AJAX. So I added UpdatePanel Control & in this control I placed Product Specifications in DataList with Checkboxes & when user selects the checkbox then I need to show products in gridview based on selection & I placed this completed code in updatePanel. Intially pages loads without errors but when i select Item from DataList the throws error..
Please help me in this regard.
Below is the sample code


<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="ProdB" runat="server" UpdateMode="Always" EnableViewState="true">
    <ContentTemplate>
        <div class="productspec-box">
            <table width="100%">
                <tbody>
                    <asp:GridView ID="gv" runat="server" ShowHeader="false" AutoGenerateColumns="false"
                        OnRowDataBound="gv_RowDataBound">
                        <Columns>
                            <asp:TemplateField>
                                <ItemTemplate>
                                    <asp:HiddenField ID="hdnAttributeId" runat="server" Value=' <%# Eval("SpecificationAttributeId") %>' />
                                    <b>
                                        <%# Eval("Name")%></b>
                                    <asp:LinkButton runat="server" ID="lnkBtn" Text='ClearAll'></asp:LinkButton>
                                    <asp:DataList ID="dlOption" runat="server" RepeatColumns="2" RepeatDirection="Horizontal">
                                        <ItemTemplate>
                                            <asp:HiddenField ID="hdnOptId" runat="server" Value='<%# Eval("SpecificationAttributeOptionId") %>' />
                                            <asp:CheckBox ID="chkList" runat="server" Text='<%# Eval("Name")%>' AutoPostBack="true"
                                                OnCheckedChanged="chkList_CheckedChanged"></asp:CheckBox>
                                        </ItemTemplate>
                                    </asp:DataList>
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:CommandField />
                        </Columns>
                    </asp:GridView>
                </tbody>
            </table>
        </div>
        <div class="product-item">
            <h2 class="product-title">
                <asp:HyperLink ID="hlProduct" runat="server" />
            </h2>
            <div class="picture">
                <asp:HyperLink ID="hlImageLink" runat="server" />
            </div>
            <div class="description">
                <asp:Literal runat="server" ID="lShortDescription"></asp:Literal>
            </div>
            <div class="add-info">
                <div class="prices">
                    <nopCommerce:ProductPrice2 ID="ctrlProductPrice" runat="server" ProductId='<%#Eval("ProductId") %>' />
                </div>
                <div class="buttons">
                    <asp:Button runat="server" ID="btnProductDetails" OnCommand="btnProductDetails_Click"
                        Text="<% $NopResources:Products.ProductDetails %>" ValidationGroup="ProductDetails"
                        CommandArgument='<%# Eval("ProductId") %>' CssClass="productgridproductdetailbutton" /><br />
                    <asp:Button runat="server" ID="btnAddToCart" OnCommand="btnAddToCart_Click" Text="<% $NopResources:Products.AddToCart %>"
                        ValidationGroup="ProductDetails" CommandArgument='<%# Eval("ProductId") %>' CssClass="productgridaddtocartbutton" />
                </div>
            </div>
        </div>

           <asp:UpdateProgress ID="up1ProdB" runat="server" AssociatedUpdatePanelID="ProdB">
                <ProgressTemplate>
                    <div class="progress">
                        <asp:Image ID="imgUpdateProgress" runat="server" ImageUrl="~/images/UpdateProgress.gif" AlternateText="update" />
                        <%=GetLocaleResourceString("Admin.Common.Wait...")%>
                    </div>
                </ProgressTemplate>
            </asp:UpdateProgress>
    </ContentTemplate>
</asp:UpdatePanel>