Hi,
I have a problem with your AutoFolders package.
I'm using:
Umbraco v4.0.2.1
Asp.net v.2.0
Windows Vista with IIS7
Stacktrace: at the end of this post
AutoFolders v1.2

The autofolders.config file is:

<?xml version="1.0" encoding="utf-8" ?>
<Settings>
     <FolderProviders>
          <FolderProvider alias="DataFolder" 
                                    assembly="/bin/AutoFolders"
                                     type="AutoFolders.Providers.DateFolderProvider">
               <Property alias="FolderDocType">News</Property>
               <Property alias="YearFormat">yyyy</Property>
         </FolderProvider>
     </FolderProviders>
     <DocTypes>
          <DocType alias="NewsItem" folderProvider="DataFolder"/>
     </DocTypes>
</Settings>

I created a node called "News" (doctype "News")
This node will contain all the "NewsItems" (doctype "NewsItem")
When I create a new NewsItem, automatically AutoFolders must create a folder with the year as name and move the NewItems into this folder.
Well...When I try to do this, I receive this error:

Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.

Stack:
[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.cms.businesslogic.web.Document.XmlPopulate(XmlDocument xd, XmlNode& x, Boolean Deep) +620
   umbraco.cms.businesslogic.web.Document.XmlGenerate(XmlDocument xd) +62
   umbraco.cms.businesslogic.CMSNode.Move(Int32 NewParentId) +530
   AutoFolders.ApplicationBase.Document_New(Document sender, NewEventArgs e) +247
   umbraco.cms.businesslogic.web.Document.OnNew(NewEventArgs e) +27
   umbraco.cms.businesslogic.web.Document.MakeNew(String Name, DocumentType dct, User u, Int32 ParentId) +980
   umbraco.contentTasks.Save() +61
   umbraco.presentation.create.dialogHandler_temp.Create(String NodeType, Int32 TypeId, Int32 NodeId, String Text) +344
   umbraco.cms.presentation.create.controls.content.doCreation() +147
   umbraco.cms.presentation.create.controls.content.sbmt_Click(Object sender, EventArgs e) +5
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +111
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +110
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

Can you help me please?
Thank you
Adriano