How can I get the author,price and title by knowing the ISBN search using amazon?

Question

How can I get the author,price and title by knowing the ISBN search using amazon in codeigniter? and

I been trying to sign up for the AProduct Advertising API registration for about 2 days, every time I get an error: We're sorry! There was an error processing your changes. Please try again. after account info step

how to get keys value of awsAccessKeyID, awsSecretKey, awsAssociateTag?

function getMetadataFromIsbn($isbn) {
    // Get your own accesskey at http://aws.amazon.com/
    $awsAccessKeyID = 'accesskey';
    $awsSecretKey = 'secrete key';
    $awsAssociateTag = 'Associate tag';
    $host = 'ecs.amazonaws.com';
    $path = '/onca/xml';    
    $args = array(
      'AssociateTag' => $awsAssociateTag,
      'AWSAccessKeyId' => $awsAccessKeyID,
      'IdType' => 'ISBN',
      'ItemId' => $isbn,
      'Operation' => 'ItemLookup',
      'ResponseGroup' => 'Medium',
      'SearchIndex' => 'Books',
      'Service' => 'AWSECommerceService',
      'Timestamp' => gmdate('Y-m-d\TH:i:s\Z'),
      'Version'=> '2009-01-06'
    );