I'm not sure exactly what you are asking here, but I can tell you the basics of how the NETLab Toolkit works.
It allows a Flash client application that you design and construct with NETLab Widgets to communicate with a server application called the NETLAB Hub. The Hub can be running on any computer, not just the one on which the Flash application is running. The communication between the Flash Widgets and the Hub is via sockets, so any IP address that is not blocked by a firewall is possible.
The computer on which the Hub is running can have an Arduino connected to it, and so a Flash application can be sending and receiving data to and from an Arduino at a remote location.
Does that answer your question?
Information about NETLab can be found here
, on its website. There are some video tutorials there also that show you, step-by-step, how to connect the Arduino to the Flash application.
Let me know if I can answer any other questions.