Webmin's LDAP Users and Groups module stopped working after upgrading from Webmin 1.400 to webmin 1.510

I have been using Webmin's LDAP Users and Groups module on my company's server to administer users. It was working fine on Webmin 1.400, but after upgrading I get the error: "Webmin has connected to the LDAP server, but failed to fetch the schema. Make sure that access has not been denied in the LDAP Server module."

I work with OpenLDAP 2.3.27 on Red Hat 5.

Thanks.

Andrea Minardi