Multiple nodes with the same URL ‘/amsV1/analysis/PupilGrades.aspx’ were found. XmlSiteMapProvider requires that sitemap nodes have unique URLs.
Solution You might want to look into the layouts.sitemap XML file in the C:\inetpub\wwwroot\wss\VirtualDirectories\<port>\_app_bin directory. In that path look in the layouts.sitemap file. This file should contain multiple entries for…