Hi, I'm trying to run some sample code which is allegedly self-contained, but the browser states I am missing a 'serializer builder' when I try to run it. Any suggestions?

Message (I took out the domain):

Warning: include(................/PHP/sample-code-php-master/PaymentTransactions/vendor/vendor/jms/serializer/src/JMS/Serializer/SerializerBuilder.php): failed to open stream: No such file or directory in ......................../PHP/sample-code-php-master/PaymentTransactions/vendor/autoload.php on line 16

Warning: include(): Failed opening '............................/PHP/sample-code-php-master/PaymentTransactions/vendor/vendor/jms/serializer/src/JMS/Serializer/SerializerBuilder.php' for inclusion (include_path='.:/opt/php54/lib/php') in ......................../PHP/sample-code-php-master/PaymentTransactions/vendor/autoload.php on line 16

Fatal error: Class 'JMS\Serializer\SerializerBuilder' not found in .................../PHP/sample-code-php-master/PaymentTransactions/vendor/lib/net/authorize/api/controller/base/ApiOperationBase.php on line 74