Question : how to avoid echo in 1 on 1 video chat / conference-system with FMS 3,5

Hi. we’ve made  an FMS 3,5 Flash video conferencing application running as an Air-application, connecting 2 persons. We’re testing it on an 10/10 Mb connection but still theres echo.
 
After 30 sec. call we’re getting echo. Does anyone know how to figure out where the echo is coming from and how to correct it?
This is not a problem with speakers too close to mic or something like - it must be something about sending/recieving packages
If we remove the video-feed theres no echo in the sound…

Anyone…? :)

thanks in advance

Answer : how to avoid echo in 1 on 1 video chat / conference-system with FMS 3,5

we found the problem ourselves :)

the problem was, that we "closed" the netStream with "null" which just deleted the reference - not killed the stream - so when calls where made we just got more and more netStreams
the solution was to maintain 4 netstreams constantly
and now we got perfect sound (even with mic and speakers in same box)