Ignited DataTables

[eluser]DiLer[/eluser]
Hey,
I just want a really simple basic working example. But for some reason it doesn't work.

The jQuery script:

Code:

$(document).ready(function() {
  $('#example').dataTable( {
  "bProcessing": true,
  "bServerSide": true,
  "sAjaxSource": "<?php echo base_url(); ?>home/getdatabyajax"
  } );
} );

The controller that outputs the json code

Code:

public function getdatabyajax()
{
  $this->load->library('Datatables');
  $this->datatables
   ->select('id,username,create_date')
   ->from('accounts');
  echo $this->datatables->generate();
}

If you open the controller (localhost/mysite/home/getdatabyajax) you get this:

Code:

{"sEcho":0,"iTotalRecords":14,"iTotalDisplayRecords":14,"aaData":[["1","test","1337976133"],["2","test2","1337976451"],["3","test3","1337976751"],["4","test4","1337976776"],["6","test5","1338072108"],["7","test6","1338152271"],["8","test7","1338400806"],["9","test8","1338400822"],["10","test9","1338400830"],["11","test10","1338400837"],["12","test11","1338400843"],["13","test12","1338400850"],["14","test13","1338400857"],["15","test14","1338400867"]],"sColumns":"id,username,create_date"}

(Just some test database)

If you open the actual page you get the table, but it only shows "Processing...".
Firebug shows me that the json code was loaded. Here is what I'm wondering: why is sEcho 0. Shouldn't that be 1? If I manually change it to 1 the data is shown inside the table. If I understand it correctly, the value should get updatet everytime I update the table. Basically a draw count. So what is going wrong?
Another thing is: shouldn't I only get the first 10 accounts, not all 14?

I'm working on this for far too long. Quite frustated right now :/
If anyone can help, I would appreciate it.
I pretty much followed this tutorial Ignited Datatables Tutorial on Vimeo

Thanks.