Web parts disappearing as soon as they are re-added to the page

Question

Our SharePoint 2003 server went down last night. Its come back online after an IIS reset, but there are various web parts missing from our landing page. When I try to re-add these components they go missing again as soon as a single page refresh happens.

When I try to open the page in SharePoint designer 2007 I receive the following error:

soap:Server Exception of type Microsoft.SharePoint.SoapServer.SoapServerException was thrown.  The file is not available. Either the file does not exist or it cannot be edited from its current location.    

How can I find what's happening here and resolve the page?

Answer 1

Although not in the IIS error logs, or the event logs this turned out to be the issue: http://support.microsoft.com/kb/823547

Putting here in the hopes I save somebody else the headaches of my morning!