Great package. 

I got the following exception when publishing my site root. (Umbraco 4.0.4.1)

I uninstalled Document Sorter package and published root successfully.

System.ArgumentExceptionNo parent node

System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.ArgumentException: No parent node
   at umbraco.cms.businesslogic.CMSNode.get_Parent() in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\cms\businesslogic\CMSNode.cs:line 260
   at TheOutfield.UmbExt.Packages.DocumentSorter.ApplicationBase.Document_Sort(Document doc, Object e)
   at umbraco.cms.businesslogic.web.Document.FireAfterSave(SaveEventArgs e) in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\cms\businesslogic\web\Document.cs:line 1323
   at umbraco.cms.businesslogic.web.Document.Save() in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\cms\businesslogic\web\Document.cs:line 434
   at umbraco.cms.presentation.editContent.Save(Object sender, EventArgs e) in d:\TeamCity\buildAgent\work\7380c184e9fcd3ea\umbraco\presentation\umbraco\editContent.aspx.cs:line 130
   at System.EventHandler.Invoke(Object sender, EventArgs e)