I have an umbraco 4.02 install on my Windows Vista PC.

Today i have experimented with the "publish at" propeerty for a page for the first time.

I set a page to publis at today at 12.00. As soon as the clock was after 12 Umbraco  crashed and now i get a server error when ever i click a page in the content tree.

I can start Umbraco and login, and everything seems normal, but if i click any page in the content tree i get this server error (YSOD):

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 Object reference not set to an instance of an object.
Beskrivelse: Der opstod en undtagelse, der ikke blev behandlet, under udførelse af den aktuelle webanmodning. Se staksporingen for at få yderligere oplysninger om fejlen, og hvor den kom fra i koden.

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

Kildefejl:

Der blev oprettet en undtagelse, der ikke blev behandlet,  under kørsel af den aktuelle webanmodning. Du kan finde oplysninger om undtagelsens oprindelse og placering ved hjælp af nedenstående staksporing af undtagelser.

Staksporing:

[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.controls.ContentControl.addControlNew(Property p, TabPage tp, String Caption) +54
   umbraco.controls.ContentControl..ctor(Content c, publishModes CanPublish, String Id) +780
   umbraco.cms.presentation.editContent.OnInit(EventArgs e) +367
   System.Web.UI.Control.InitRecursive(Control namingContainer) +333
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +378

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This happend at the same time the page was set to publish, but i'm not sure that there is a connection ???

What happend ?

What can i do to get my Umbraco install to work again.

Thanks,  merry X and happy new year to all.

Mikael