Did you try to switch these two lines mentioned in the article from Roman?
As I stated above, Kentico currently creates a jQuery alias. What you need to do is open the jquery-core.js file and locate the line stating:
var $cmsj = jQuery.noConflict();
Comment this line and then uncomment the line:
var $cmsj = jQuery.noConflict(true);
Also what namespace are you using for your custom jQuery?
Best regards, Martin