Anonymous access to KM


We have setup anonymouys access for KM by following the sap note 837898.

When opening some documents via Content Administration -> KM Content -> KM content, we recieve an 403 error. The stacktrace thats part of this message is

com.sapportals.wcm.protocol.webdav.server.WDServletException: Permission denied: uri=/documents/test/test.txt, permission=leaf_read_content, user=anonymousEmployee

I'm logged on with my userid, which is part of the Administrators group. The Administrators group has full access to the above KM location.

Can someone explain why the portal is trying to logon with the anonymous user, although I'm logged on as part of Administrators group and have access to the KM resource ?

Thanks a lot!