When I Enable the Facebook Authentication in the Admin Extensions, I get an exception that keeps the Login page from loading:

DotNetNuke.Services.Exceptions.PageLoadException: Invalid URI: The format of the URI could not be determined. ---> System.UriFormatException: Invalid URI: The format of the URI could not be determined. at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind) at System.Uri..ctor(String uriString) at DotNetNuke.Services.Authentication.OAuth.OAuthClientBase..ctor(Int32 portalId, AuthMode mode, String service) at DotNetNuke.Authentication.Facebook.Components.FacebookClient..ctor(Int32 portalId, AuthMode mode) at DotNetNuke.Authentication.Facebook.Login.OnInit(EventArgs e) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.AddedControl(Control control, Int32 index) at System.Web.UI.ControlCollection.Add(Control child) at DotNetNuke.Modules.Admin.Authentication.Login.BindOAuthControls() at DotNetNuke.Modules.Admin.Authentication.Login.BindLogin() at DotNetNuke.Modules.Admin.Authentication.Login.ShowPanel() at DotNetNuke.Modules.Admin.Authentication.Login.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---

Any idea what URL is being rejected here?