newbie: menu problem

[Jeff]

hey

asp.net 2.0

I've created a simple website where I could play arround with the new site
navigation sytem provided in asp.net 2.0

When I run my webpage I get this error:

Description: An error occurred during the processing of a configuration file
required to service this request. Please review the specific error details
below and modify your configuration file appropriately.

Parser Error Message: The provider 'XmlSiteMapProvider' specified for the
defaultProvider does not exist in the providers collection.

Source Error:

Line 12: <connectionStrings/>
Line 13: <system.web>
Line 14: <siteMap defaultProvider="XmlSiteMapProvider">
Line 15: <providers>
Line 16: <add

Part of my web.config file:
<siteMap defaultProvider="XmlSiteMapProvider">
<providers>
<add
name="SidebarMenuA"
type="System.Web.XmlSiteMapProvider"
siteMapFile="Web.sitemap"/>
</providers>
</siteMap>

Part of Default.aspx:
<form id="form1" runat="server">
<div>
&nbsp;
<asp:Menu ID="Menu1" runat="server" BackColor="#F7F6F3"
DataSourceID="SiteMapDataSource1"
DynamicHorizontalOffset="2" Font-Names="Verdana" Font-Size="0.8em"
ForeColor="#7C6F57"
StaticSubMenuIndent="10px" Style="z-index: 100; left: 11px;
position: absolute;
top: 10px" Width="202px">
<StaticMenuItemStyle HorizontalPadding="5px"
VerticalPadding="2px" />
<DynamicHoverStyle BackColor="#7C6F57" ForeColor="White" />
<DynamicMenuStyle BackColor="#F7F6F3" />
<StaticSelectedStyle BackColor="#5D7B9D" />
<DynamicSelectedStyle BackColor="#5D7B9D" />
<DynamicMenuItemStyle HorizontalPadding="5px"
VerticalPadding="2px" />
<StaticHoverStyle BackColor="#7C6F57" ForeColor="White" />
</asp:Menu>
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" />
</div>
</form>

I based my work on this article
http://msdn2.microsoft.com/en-us/library/ms178426(d=printer).aspx

I want to learn how to combine different .sitemap files for the site
navigation.... For example one .sitemap file for the header.. and another
..sitemap file for the sidemenu (I'm developing another webportal where I
don't want to use drop down menus, but a sidebar menu which show menu items
related to the item selected in the main menu - 2 menu controls on the same
page, but first I have to learn how to use site navigation in asp.net 2.0.).

Any ideas why I get this error?

Jeff