Big Problem about Ldap

[eluser]bertico[/eluser]
hello. I am working with a ldap server. but it returns me to following error:

Fatal error: Uncaught SoapFault exception: [soap:Client] Parámetro vacío in C:\AppServ\www\Caracterizacion\system\application\controllers\inicio.php:40 Stack trace: #0 [internal function]: SoapClient->__call('ObtenerPersonaD...', Array) #1 C:\AppServ\www\Caracterizacion\system\application\controllers\inicio.php(40): SoapClient->ObtenerPersonaDadoLogin('ermorales') #2 [internal function]: Inicio->loger() #3 C:\AppServ\www\Caracterizacion\system\codeigniter\CodeIgniter.php(216): call_user_func_array(Array, Array) #4 C:\AppServ\www\Caracterizacion\index.php(132): require_once('C:\AppServ\www\...') #5 {main} thrown in C:\AppServ\www\Caracterizacion\system\application\controllers\inicio.php on line 40

who can tell me the problem that to cause this error and how I can to solve it?
thanks...