[horde] The usernames are not displayed

[Raul Pineiro]

I'm using horde (3.2) on Windows 2000 server platform.
The users are authenticated on Active Directory using LDAP, but  I've got
some problems for list theirs when I select  the administration option
called "Users". Theirs usernames (samaccountname attribute for AD) are not
displayed.
I have put the filter to search users (&(sn=*)(ObjectClass=person)), and I
think that it is correct.
What am i doing wrong?
Thanks