A PHP Error was encountered [Help]

[eluser]kikz4life[/eluser]
thanks for the reply Brian,

found my error, forgot to add this line to my js file: mtype: 'POST', but now my a new problem arise and this is what i found in my firebug logs. As you can see, i was able to query the the data but im not getting anything in return.

Code:

{"page":"1","total":2,"records":"11","rows":[{"id":"1","cell":
{"role_id":"1","role_code":"ADMIN","role_desc":"admin"}},{"id":"2","cell":
{"role_id":"2","role_code":"CEO","role_desc":"CEO"}},{"id":"3","cell":
{"role_id":"3","role_code":"DIVMANAGER","role_desc":"Division Manager"}},{"id":"4","cell":
{"role_id":"4","role_code":"FINANCE","role_desc":"Finance"}},{"id":"5","cell":
{"role_id":"5","role_code":"PROJMANAGE","role_desc":"Project Manager"}},{"id":"6","cell":
{"role_id":"6","role_code":"SALESLADY","role_desc":"Sales Associate"}},{"id":"7","cell":
{"role_id":"7","role_code":"SALESMAN","role_desc":"Sales Manager"}},{"id":"8","cell":
{"role_id":"8","role_code":"leirons","role_desc":"Super User"}},{"id":"14","cell":
{"role_id":"14","role_code":"JC","role_desc":"Junior Consultant"}},{"id":"15","cell":
{"role_id":"15","role_code":"SDSDFSF","role_desc":"SFSDFSDF"}}]}<br />

<b>Fatal error</b>:  ob_start() [&lt;a href='ref.outcontrol'&gt;ref.outcontrol&
lt;/a&gt;]: Cannot use output buffering in output buffering display handlers in
<b>C:\xampp\htdocs\myweb\system\libraries\Exceptions.php</b> on line <b>162</b><br />

i trace it in this library and its this line:
ob_start();

but i doubt this is the real problem here.