Not able to get AMFPHP up and running

When doing a clean install of Drupal 5.x (tested with 5.3, 5.4 and 5.5), and downloading latest servicesmodule, amfphpmodule, and amfphp beta2

I enable them in Site Building -> Modules, then go to Site Building -> Services and press amfphp to test it, I get:

Fatal error: Uncaught exception 'VerboseException' with message 'realpath(): Unable to access /(...)/drupal/services//' in /(...)/drupal/modules/amfphp/amfphp/core/amf/app/Gateway.php:296 Stack trace: #0 [internal function]: amfErrorHandler(2, 'realpath(): Una...', '/(...)/w...', 296, Array) #1 /(...)/drupal/modules/amfphp/amfphp/core/amf/app/Gateway.php(296): realpath('services//') #2 /(...)/drupal/modules/amfphp/amfphp.module(47): Gateway->setClassPath('services/') #3 [internal function]: amfphp_server() #4 /(...)/drupal/includes/module.inc(386): call_user_func_array('amfphp_server', Array) #5 /(...)/drupal/modules/services/services.module(239): module_invoke('amfphp', 'server') #6 [internal function]: services_server('amfphp') #7 /(...)/drupal/includes/menu.inc(418): call_user_func_array('services_server', Array) #8 /(...)/drupal/index.php(15): menu_execute_active_handler() #9 { in /(...)/drupal/modules/amfphp/amfphp/core/amf/app/Gateway.php on line 296