socket.io + haproxy, having some proxy set-up issues

node.log

   info  - socket.io started
25 Jun 21:09:25 - Server started on port 8124
127.0.0.1 - - [Sun, 26 Jun 2011 01:09:32 GMT] "GET /require.js HTTP/1.1" 200 - "http://kriegspiel.carpeliam.com/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.100 Safari/534.30"
   debug - served static /socket.io.js
   debug - client authorized
   info  - handshake authorized
   info  - handshaken 2411a4f640f1ac6684614b98bc7a95d5
127.0.0.1 - - [Sun, 26 Jun 2011 01:09:33 GMT] "GET /favicon.ico HTTP/1.1" 404 - "" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.100 Safari/534.30"
   debug - setting request GET /socket.io/1/websocket/2411a4f640f1ac6684614b98bc7a95d5
   debug - publishing that 2411a4f640f1ac6684614b98bc7a95d5 connected
   debug - initializing client store for 2411a4f640f1ac6684614b98bc7a95d5
   debug - set heartbeat interval for client 2411a4f640f1ac6684614b98bc7a95d5
   debug - subscribing 2411a4f640f1ac6684614b98bc7a95d5
EXCEPTION: TypeError: Argument must be a string
undefined
   debug - emitting heartbeat for client 2411a4f640f1ac6684614b98bc7a95d5
   debug - websocket writing 2::
   debug - set heartbeat timeout for client 2411a4f640f1ac6684614b98bc7a95d5
   debug - websocket received data packet 2::
   debug - got heartbeat packet
   debug - cleared heartbeat timeout for client 2411a4f640f1ac6684614b98bc7a95d5
   debug - set heartbeat interval for client 2411a4f640f1ac6684614b98bc7a95d5
   debug - emitting heartbeat for client 2411a4f640f1ac6684614b98bc7a95d5