Cannot save changes C++ exception

[Xed]

We are getting the message:
An unexpected error occurred while accessing your
FrontPage Web files.
Authors - If authoring against a web server please
contact the
webmaster
for this server's site. WebMasters please see the
server's system log
for more details.

The server event log event (ID: 1000) is:
Microsoft FrontPage Server Extensions:
unexpected C++ exception: [MAGIC] Bad magic number: 108
(should be 4661)

We are being prevented from making any changes to the
navigation structure. Files can be saved but it says it
can't write them to the existing file, forces a save under
a different name but then the original is also updated
when it is inspected.

One clue is that the server hung while doing a top-level
navigation structure update (to a large site).

Any clues? There's nothing at all (that I can find) in the
KB, closest is KB198123.

Cheers

 

[Telchar]

The problem is probably that one of the two .BTR files is
corrupted in the _vti_pvt folder at the web root level.
Try restoring a working back-up and seeing if that works.

=====
In Moria, in Khazad Dum