Redmine

I'm trying to configure LDAP authentication against a local LDAP server (same machine). I get the following error:

Unable to connect (can't convert Net::LDAP::LdapError into String)

I find no indication that a connection is being made neither in the redmine logs (I enabled debug logging) nor in the syslog (where slapd logs to). I also tried monitoring the packets going over the lo interface. I see traffic when I access ldap using other services, but not redmine. Here is my configuration (excluding the domain):

Name Redmine LDAP
Host localhost
Port 389 LDAPS No
Account cn=admin,dc=myrealdomain,dc=com
Password *****
Base DN ou=people,dc=myrealdomain,dc=com
On-the-fly user creation No
Attributes
Login uid
Firstname givenName
Lastname sn
Email mail

I'm using OpenLDAP server on Ubuntu 8.04.03 LTS. Here are the details on my environment:

About your application's environment
Ruby version 1.9.1 (i686-linux)
RubyGems version 1.3.5
Rack version 1.0
Rails version 2.3.5
Active Record version 2.3.5
Active Resource version 2.3.5
Action Mailer version 2.3.5
Active Support version 2.3.5
Application root /var/www/redmine
Environment production
Database adapter mysql
Database schema version 20091227112908