Problem with jQuery ajax (not validating data)

[eluser]gon[/eluser]
Try using firebug extension for firefox.
It allows you to monitor ajax calls and check visually that all params are ok.
Also, you can right-click on any ajax POST call and open it as if it was a normal POST form.
So you can reload the page and put some var_dumps et al.

Hope it helps.
I don't have the time to check where your error might be, just to give some advice on how to debug ajax.

BTW, I do ajax validations in CI with no problem.

Regards.