Seems like today it's very simple to get good comunication betwen flash (frontend) and drupal 7 (backend), good people had wrote just great API to make your work as simple as possible... but there are spots even in the sun. Here are my steps to make them workin' on D7 + Flex SDK 4.5.
It took me hours to solve the problem with continuous "NetConnection.Call.Failed" on Flash/Flex, server side AMF3 parser keeps receiving empty data array... Showing notices at watchdog: Notice: Undefined offset: 0 in Zend_Amf_Request->readBody() (line 186 of .\sites\all\libraries\Zend\Amf\Request.php). and various Zend_Amf_Exceptions... Want to know how to solve it?