ReferenceError: Class is not defined #4

Followed the instructions, but when i do node app.js, this is the error I get:

ReferenceError: Class is not defined
at Object. (/var/www/myproject/lib/facebook.js:7:21)
at Module._compile (node.js:462:23)
at Module._loadScriptSync (node.js:469:10)
at Module.loadSync (node.js:338:12)
at loadModule (node.js:283:14)
at require (node.js:411:14)
at Object. (/var/www/myproject/app.js:6:1)
at Module._compile (node.js:462:23)
at Module._loadScriptSync (node.js:469:10)
at Module.loadSync (node.js:338:12)

Regards