I tried to upgrade freeradius-server-2.1.6 to freeradius-server-2.1.7 and it worked well (in localhost) without ldap.Then I tried to use the old version (2.1.6) but it doesn't work anymore:
Thu Sep 24 13:32:16 2009 : Error: /usr/local/freeradius-server-2.1.6//etc/raddb/                                                                                        modules/ldap[29]: Failed to link to module 'rlm_ldap': libldap_r-2.3.so.0: canno                                                                                        t open shared object file: No such file or directory