That can happen if the server is busy, thats why there is a random number to chose servers, wait 30+ seconds and it will use other server for connection.
I'm also using the latest rtmpdump from KSV:
http://stream-recorder.com/forum/cus...le-t16103.html
EDIT: But if you said that you always get that error, then I'm not sure what can be (firewall problems?).