sessions not saved when socket.io starts - node.js

Question

I have strange problem and I don't have any clue whats happening. Somehow sessions are not saved to redis anymore when I start socket.io, but when I comment out socket.io they work. The code can be found here: nothing unusual. This code stopped working after a db crash. When I tried to run the app again, it said that redis connection is already in use. I found and killed the node process that was using this connection, and I'm able to start my app again, but now there is this issue with sessions.
var config = require('./config')
, express = require('express')
, routes = require('./routes')
, RedisStore = require('connect-redis')(express)
, sessionStore = new RedisStore(config.redis)
, app = express.createServer();
app.configure(function () {
app.use(express.static(__dirname + '/public'));
app.use(express.cookieParser('keyboard cat'));
app.use(express.session({
secret: config.sessionSecret,
key: 'express.sid',
store: sessionStore
}));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
})
app.configure('development', function () {
app.use(express.errorHandler());
});
app.enable('jsonp callback');
routes.init(app);
app.listen(config.port);
console.log("listening on port " + config.port);
// socket.io
var io = require('socket.io').listen(app);
io.configure(function() {
io.set("polling duration", 10);
io.enable('browser client minification');
io.enable('browser client etag');
io.enable('browser client gzip');
io.set('log level', 3);
io.set('transports', ['xhr-polling']);
}
);