AJAX :: Sys.WebForms.PageRequestManagerServerErrorException: An Unknown Error Occurred While Processing?

I am getting this error message (in IE) when i click on any of the menu items used in my code, i pasting my code here, please review it and suggest me the corrections, i have tried reading other similar articles which mentioned increasing maxReuestLength(<httpRuntime maxRequestLength="8192" />) but it hasn't solved my problem.

<asp:UpdatePanel ID="UpdatePanel1cc" runat="server">
<ContentTemplate>
<asp:Menu
id="menuTabs"
CssClass="menuTabs"
StaticMenuItemStyle-CssClass="tab"
StaticSelectedStyle-CssClass="selectedTab"
Orientation="Horizontal"
Runat="server" onmenuitemclick="menuTabs_MenuItemClick">
<Items>
<asp:MenuItem
Text="Jan"
Value="jan" />
<asp:MenuItem
Text="Feb"
Value="Feb"
Selected="true" />
<asp:MenuItem
Text="Mar"
Value="Mar" />
</Items>
</asp:Menu>
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>Updating...</ProgressTemplate>
</asp:UpdateProgress>