In addition to Malte's posting:
It seems to be that M$ Office trys WebDAV in order to load and save documents directly from and to the web.
See also:
http://support.microsoft.com/?scid=kb;en-us;838028
(How documents are opened from a Web site in Office 2003)
In the case Malte describes, there exist log entries like that:
192.168.42.111 - - [19/Jul/2006:14:17:59 +0200] "OPTIONS
/dotlrn/path/example.doc?file%255fid=4711
HTTP/1.1" 404 544 "" "Microsoft Data Access Internet Publishing Provider Protocol Discovery" 0.000145...
192.168.42.111 - - [19/Jul/2006:14:19:45 +0200] "OPTIONS
/dotlrn/path/ HTTP/1.1" 404 544 ""
"Microsoft Office Protocol Discovery" 0.000288...
OPTIONS is regular/legal HTTP... see http://www.ietf.org/rfc/rfc2616.txt
I added the following to the robots.txt
User-agent: Microsoft Office Protocol Discovery
Disallow: /
but it does not have any effect.
Ideas and hints are appreciated.
Greetings,
Nils