Cannot set property 'twitter_oauth_token_secret' of undefined

[benzen]

I was trying to follow the express/twitter exemple

Now i've got this error

TypeError: Cannot set property 'twitter_oauth_token_secret' of undefined at /home/dotcloud/node_modules/connect-auth/lib/auth.strategies/twitter.js:85:63 at /home/dotcloud/node_modules/connect-auth/node_modules/oauth/lib/oauth.js:518:7 at passBackControl (/home/dotcloud/node_modules/connect-auth/node_modules/oauth/lib/oauth.js:359:11) at IncomingMessage. (/home/dotcloud/node_modules/connect-auth/node_modules/oauth/lib/oauth.js:378:9) at IncomingMessage.emit (events.js:81:20) at HTTPParser.onMessageComplete (http.js:133:23) at Socket.ondata (http.js:1228:22) at Socket._onReadable (net.js:683:27) at IOWatcher.onReadable as callback

Do you have an idea about what is the problem here??