I developed a web application that uses socket.io on my windows platform, and it worked perfectly. However, as soon as I move it over to my debian 6 production dedicated server, it starts dropping clients for "warn - websocket connection invalid".
This error happens on the server, and drops normally 10-20 seconds after the first connection is established.
socket.io is running at version 0.9.11 on both linux + windows servers
Did you check your ports and connection adresses?
Try updating your socket.io!