hi i am trying to access UPS Shipping webservices ... by using nusoap but it always said "No Access and Authentication Credentials provided " here is my code

$lead=array();
$lead['Request']="";
$lead['TransactionReference']="";
$lead['ShipFrom']="";
$lead['Address']="";
$lead['City']="BethPage";
$lead['StateProvinceCode']="NY";
$lead['PostalCode']="11714";
$lead['ShipTo']="";
$lead['Address']="US";
$lead['City']="Flushing";
$lead['StateProvinceCode']="NY";
$lead['PostalCode']="11358";
$lead['Pickup']="";
$lead['Date']="20071028";
$lead['ShipmentWeight']="";
$lead['UnitOfMeasurement']="";
$lead['Code']="KGS";
$lead['Description']="Kilograms";
$lead['Weight']="10";
$lead['InvoiceLineTotal']="";
$lead['CurrencyCode']="USD";
$lead['MonetaryValue']="1000";
$lead['DocumentsOnlyIndicator']="";


$soapclient = new soapclient($soap_master_file); //define the SOAP Client and point to the SOAP Server
$soapclient->response_timeout = 60;
$soapclient->setHeaders("<Security> <UsernameToken> <Username>$username</Username> <Password>$password
</Password> </UsernameToken><UPSServiceAccessToken> <AccessLicenseNumber>
$accessKey </AccessLicenseNumber> </UPSServiceAccessToken></Security>");
$soapclient->setCredentials('$username','$password');

$result=$soapclient->call('GetRate', array('RateRequest'=>$lead),'','http://wwwcie.ups.com/webservices/RateBinding');

echo '<pre>' . htmlspecialchars($soapclient->request, ENT_QUOTES) . '</pre>';

you may want to try to surround arguments in an extra array:
$result=$soapclient->call('GetRate', array(array('RateRequest'=>$lead)), ...
also you need to check the URL for the namespace. What you posted does not work.
finally, if $soap_master_file is a WSDL filename or URL, you have to provide 2nd argument in the soapclient constructor call. See samples in this forum.