define-key turns to go the wrong way.

[Peng Dai]

I use ubuntu12.04(32bit,US), and emacs24.2. When I descide to have a new key
"\C-[" and "\C-]" to scroll my window,

so I write the following in the init.el

(global-set-key (kbd "\C-]") (lambda () (interactive) (scroll-up 2)))
(global-set-key (kbd "\C-[") (lambda () (interactive) (scroll-down 2)))

this first is work fine. but the second didn't work.
When I use the "\C-h k" to see what' wrong. It turn out to be "\C-[" was readed 
as "<ECS>". I search the google with no result, it says it was because of the 
ISCAE's key value but with no soluvation give.

And I find another key has the same problem,too. like:
"\C-j" turn to be "<SPACE>"
"\C-M-j" turn to be "<RET>j"

Can anyone help.