LDAP pagination requires protocol version 3+. If the LDAP_CONTROL_PAGEDRESULTS LDAP control is not working for you, try setting the LDAP protocol version before binding:
<?php
$ldapconn = ldap_connect($ldapuri) or die("That LDAP-URI was not parseable");
ldap_set_option($ldapconn, LDAP_OPT_PROTOCOL_VERSION, 3);
?>