http://bugs.winehq.org/show_bug.cgi?id=26456
--- Comment #2 from Hans Leidekker hans@meelstraat.net 2011-03-17 10:03:31 CDT --- Created an attachment (id=33689) --> (http://bugs.winehq.org/attachment.cgi?id=33689) wldap32: Accept NULL value in ldap_set_option.
Try this patch.