Hi,

all of a sudden i can't hit the "Save and publish" button on my home node without an YSOD anymore.
What i can do without an exception is:
- hit the Save" button
- publish the node via context menu: "Publish" (what is the difference to the "Save and publish" button?)

This is a part of UmbracoTraceLog.txt: 

2013-01-24 09:51:05,470 [17] WARN  Umbraco.Web.Routing.NiceUrlProvider - [Thread 5] Couldn't find any page with nodeId=0. This is most likely caused by the page not being published.
2013-01-24 09:51:05,470 [17] WARN  Umbraco.Web.Routing.NiceUrlProvider - [Thread 5] Couldn't find any page with nodeId=0. This is most likely caused by the page not being published.
2013-01-24 09:51:05,470 [17] WARN  Umbraco.Web.Routing.NiceUrlProvider - [Thread 5] Couldn't find any page with nodeId=0. This is most likely caused by the page not being published.
2013-01-24 09:51:05,517 [17] ERROR Umbraco.Web.UmbracoApplication - [Thread 5] An unhandled exception occurred
System.Web.HttpUnhandledException (0x80004005): System.ArgumentNullException: Value cannot be null.
Parametername: attribute
   bei System.Xml.Linq.XAttribute.op_Explicit(XAttribute attribute)
   bei UmbracoExamine.UmbracoContentIndexer.ReIndexNode(XElement node, String type)
   bei Examine.ExamineManager._ReIndexNode(XElement node, String type, IEnumerable`1 providers)
   bei umbraco.content.DocumentCacheEventHandler.Invoke(Document sender, DocumentCacheEventArgs e)
   bei umbraco.content.UpdateDocumentCache(Document d)
   bei umbraco.library.UpdateDocumentCache(Document doc)
   bei umbraco.cms.presentation.editContent.Publish(Object sender, EventArgs e)
   bei System.EventHandler.Invoke(Object sender, EventArgs e)
   bei System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e)
   bei System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument)
   bei System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   bei System.Web.UI.Page.HandleError(Exception e)
   bei System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   bei System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   bei System.Web.UI.Page.ProcessRequest()
   bei System.Web.UI.Page.ProcessRequest(HttpContext context)
   bei System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   bei System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I read a lot of posts about this exception, but none of the solutions worked for me (e.g. deleting examine index, rebuild the entire XML,...).

Some more info:
- i don't have any special characters in my document type names
- i didn't install any new packages before it stopped working
- i don't use any event handlers
- when i create a new node based on the same document type, publishing works

Any hints?

Thanks,
Matthias