authentication by openldap

[Isabelle Heu <heu@istpc41.cicrp.jussieu.fr>]

hello,
I've got 
openldap-2.1.29-1
 openldap-servers-2.1.29-1
 openldap-clients-2.1.29-1
 openldap-devel-2.1.29-1
 nss_ldap-217-1

and i'm trying to authenticate.
i can login locally in text mode but i cannot in graphical mode.

i got this in my log:
	Jul 27 13:12:22 istpc13 gdm(pam_unix)[2450]: check pass; user unknown
	Jul 27 13:12:22 istpc13 gdm(pam_unix)[2450]: authentication failure; logname= 			
uid=0 euid=0 tty=:0 ruser= rhost=
	Jul 27 13:12:22 istpc13 gdm(pam_unix)[2450]: could not identify user (from 
getpwnam(heu))

though i get the correct userid by 
perl -e '($name,$passwd,$uid,$gid) = getpwnam($ARGV[0]); print $uid' heu

thanx for your help.

-- 
Isabelle Heu
Institut de Sciences et Technologie
Univ. Paris 6