Exception:

Object reference not set to an instance of an object.

Stack Trace:

at DotNetNuke.Entities.Urls.FriendlyUrlController.GetTabs(Int32 portalId, Boolean includeStdUrls, PortalSettings portalSettings, FriendlyUrlSettings settings) at DotNetNuke.Entities.Urls.FriendlyUrlController.GetTabs(Int32 portalId, Boolean includeStdUrls, FriendlyUrlSettings settings) at DotNetNuke.Entities.Urls.TabIndexController.BuildTabDictionary(PathSizes& pathSizes, FriendlyUrlSettings settings, Int32 buildPortalId, SharedDictionary`2 tabIndex, Hashtable& homePageSkins, SharedDictionary`2& portalTabPathDictionary, Guid parentTraceId) at DotNetNuke.Entities.Urls.TabIndexController.FetchTabDictionary(Int32 portalId, Int32& minTabPathDepth, Int32& maxTabPathDepth, Int32& minAliasPathDepth, Int32& maxAliasPathDepth, FriendlyUrlSettings settings, Boolean forceRebuild, Boolean bypassCache, Guid parentTraceId) at DotNetNuke.Entities.Urls.RewriteController.GetTabFromDictionary(String url, NameValueCollection querystringCol, FriendlyUrlSettings settings, UrlAction result, Guid parentTraceId) at DotNetNuke.Entities.Urls.RewriteController.IdentifyByTabPathEx(String absoluteUri, String queryString, UrlAction result, NameValueCollection queryStringCol, FriendlyUrlSettings settings, Guid parentTraceId) at DotNetNuke.Entities.Urls.AdvancedUrlRewriter.CheckForRewrite(String fullUrl, String querystring, UrlAction result, Boolean useFriendlyUrls, NameValueCollection queryStringCol, FriendlyUrlSettings settings, Boolean& isPhysicalResource, Guid parentTraceId) at DotNetNuke.Entities.Urls.AdvancedUrlRewriter.ProcessRequest(HttpContext context, Uri requestUri, Boolean useFriendlyUrls, UrlAction result, FriendlyUrlSettings settings, Boolean allowSettingsChange, Guid parentTraceId)

Administrators

You can see this exception because the customErrors attribute in the web.config is set to 'off'. Change this value to 'on' or 'RemoteOnly' to show Error Handling

The error handling would have shown this page :