FMS (Flash Media Server) problem

We have a problem with an application written for us that uses FMS. The problem is that under a FMS test license the application works fine, but FMS limits the users to approx 10 connections. We have purchased the license key for FMS and when it enter it the application stops working. We get the error: "application is not a valid signed application loading access denied". If we remove the license Key the application works again. We need to someone to solve this issue for us.