Windows Backup error
 

I try to backup my Vista system to a remote file share. This worked fine for
a year and now I get an error

Event ID 4104"Event Source: Windows Backup and

An error occurred. The following information might help you resolve the
error:

The specified network name is no longer available.
(0x80070040)


What can be the reason. It just suddenly stooped working. Is there
anywhere more log information available ?

Thank you
Markus