Using Winbind rather than pam_ldap can me more reliable at times. These days, you don’t need smbd/nmbd for winbindd to work though. Unfortunately, it sounds like you did once and most the documentation out there says as much.

On debian etch:

Stopping /etc/init.d/samba and winbind, then starting winbind worked fine, winbind appears to default to dual daemon mode, so you don’t need to enable as much in /etc/defaults/winbind these days, ‘-Y’ sets it back to single daemon mode.

Also you’ll notice the init script doesn’t require samba.

#!/bin/sh

### BEGIN INIT INFO
# Provides:          winbind
# Required-Start:    $network $local_fs $remote_fs
# Required-Stop:     $network $local_fs $remote_fs
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: start Winbind daemon
### END INIT INFO