Thank you, chatwizrd!
The logs recorded php:
[10-Jun-2014 12:37:19 Europe/Moscow] PHP Warning: PHP Startup: in Unknown on line 0
[10-Jun-2014 12:38:43 Europe/Moscow] PHP Warning: ldap_start_tls(): Unable to start TLS: Can't contact LDAP server in C:\www\mail\program\lib\Roundcube\rcube_ldap_generic.php on line 179
[10-Jun-2014 12:38:43 Europe/Moscow] PHP Fatal error: Cannot break/continue 1 level in C:\www\mail\program\lib\Roundcube\rcube_ldap_generic.php on line 180