What does this error in http.log mean : Fetchcomponents_by_range_reply_access ?

In my http.log I have lines like :

>

> [05/Nov/2001:10:30:11 +0100] ldap cshttpd[124]: General Error: ac:

> Fetchcomponents_by_range_reply_access: User "agenda" denied access on

> fetching from calendar "5A80".

> [05/Nov/2001:10:30:11 +0100] ldap cshttpd[124]: General Error: ac:

> Fetchcomponents_by_range_reply_access: User "agenda" denied access on

> fetching from calendar "5B92".

> [05/Nov/2001:10:30:11 +0100] ldap cshttpd[124]: General Error: ac:

> Fetchcomponents_by_range_reply_access: User "agenda" denied access on

> fetching from calendar "3B42".

Those calendars exist (5A80, 5B92, 3B42), and the everyone user has full control over those calendars.

[771 byte] By [709026] at [2007-11-25 4:41:31]