My Casperjs test fails on div taken form FB page, but the same test on Google page works, why?

this is my code, it works on element(div) taken from Google page, 3 tests pass, but when i do the same on element(div) from facebook page test fails;

    Here's the code:

    var x = require('casper').selectXPath;


    casper.userAgent("Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36");

    casper.test.begin("test", function(test) {
    // step 1: open the page.
    casper.start("https://facebook.com/", function() {
    // do an example test.
    test.assertTitle("");
    console.log("test title of the page");
    casper.capture('startingpage1.png');

    });
    casper.wait(2000, function(){
    casper.capture('startingpage2.png');

    });

    // step 2: take some screenshots.
    casper.then( function () {
    // Powinno dzialac, na google dziala
    casper.test.assertExists('div#registration_container');
    });

    casper.wait(1000, function () {

    test.assertVisible('div#registration_container', "... element is   visible.");
    this.capture("start55.png");
    });




    // actually run the steps we defined before.
    casper.run(function() {
    test.done();
    });
    });

PASS Page title is: ""
test title of the page
FAIL Find an element matching: div#registration_container
#    type: assertExists
#    file: wysiwygTest.js:23
#    code: casper.test.assertExists('div#registration_container');
#    subject: false
#    selector: "div#registration_container"
FAIL ... element is visible.
#    type: assertVisible
#    file: wysiwygTest.js:28
#    code: test.assertVisible('div#registration_container', "... element is visible.");
#    subject: false
#    selector: "div#registration_container"
FAIL 3 tests executed in 3.561s, 1 passed, 2 failed, 0 dubious, 0 skipped.

Maybe i'm missing something in my code or i didn't install and configure everything properly? Maybe there are some differences with build of these two pages, so the code works on 1 but it doesn't on second? So i would be grateful if someone explain it to me. I would be very grateful, if someone could tell me how to fix this problem.Thanks in advance, Michal Sawicki.