Has anyone seen an error occur when a user performs the edit in excel action and the user gets an authentication prompt which they can't get past with their correct credentials and then a similar error occurs as if the server had gone offline (Office 2003 on Win XP against WSS 3.0 SP2)
The users can get to the document fine via other methods i.e. if the download a copy from SharePoint instead of edit. It looks like the error is down in the RPC layer as the call is to author.dll and the following is logged.
10/12/2009 09:26:28.62 w3wp.exe (0x0D90) 0x02D8 Windows SharePoint Services General 72ng Medium RPC method = checkout document
10/12/2009 09:26:28.87 w3wp.exe (0x0D90) 0x1274 1463 8l41 High assertPermissionMask was called, but permissions haven't been computed yet.
Any suggestions on fixes or ways to debug would be great !