sorry because I had asking the same question before. here is the url CodeIgniter : Disallowed key Characters in Chrome.
I was solving the problem by deleting _ (underScore) in URL. at that time, the problem was solved. later, CodeIgniter give me a Disallowed Key Characters error again and always. I had asking this question in a PHP group in Indonesia, and someone gives me solution that I must delete the cookies in my browser. when I delete the cookies, my application is working well. But several days later, the error is comeback again. Then, I delete the cookies again. It happens over and over again. I don't know what is the point causing this error. For information, I'm using jquery Jtable plugin. I don't know what the relation between this error and jtable plugin but it is first time happen when I was implementing jtable plugin in my application. Anyone have any ideas what I can do to fix this??