Configuring SSL for LDAP

Error <0x51> = ldap_set_option(hLdap, LDAP_OPT_PROTOCOL_VERSION,

Error <0x51> = ldap_connect(hLdap, NULL);
Server error: <empty>
Error <0x51>: Fail to connect to localhost.

> How can I enable SSL in Active Directory? I can currently connect to
> port 389 using ldp, but when trying to connect using SSL to port 636 I
> get the following error:
> ld = ldap_sslinit("localhost", 636, 1);
> Error <0x51> = ldap_set_option(hLdap, LDAP_OPT_PROTOCOL_VERSION,
> LDAP_VERSION3);
> Error <0x51> = ldap_connect(hLdap, NULL);
> Error <0x51>: Fail to connect to localhost.
> Any pointers/help in this regard would be very much appreciated.
> Thank you,
> Bob
>