Кодировка не причем. Проверил.
[Mon Jul 2 12:19:44 2012][Notice][Kernel::System::CustomerAuth::LDAP::Auth] CustomerUser: otrs@mydomain.ru (CN=otrs,DC=mydomain,DC=ru) authentication ok (REMOTE_ADDR: 127.0.0.1).
[Mon Jul 2 12:19:44 2012][Error][Kernel::System::CustomerUser::SetPreferences][504] No such user 'otrs@mydomain.ru'!
