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??