I have received this error, but don't know what it means:

System.Configuration.ConfigurationErrorsException: Exactly one <siteMapNode> element is required directly inside the <siteMap> element.

Can you help me?

+6  A: 

Could be something with sitemap... I googled and found this:

The site map has to have a single root siteMapNode element, underneath which all other elements reside. So you have:

    <siteMapNode title="Home" ...>
        all other nodes

This means that all nodes are at least a child of the root node. When displaying the Menu you can chose to not show the root node, or to show both it and the child nodes together.