Problem with fluxbox resolution and ATI driver

[asdf737]

Hi all.
My fluxbox screen is ugly. When i try to change res with xrandr, it says:

Cant open display.

First i was try with xorg-drivers, second with ati-drivers. But problem is same in both of cases.
I have ATI Radeon HD4600.
VIDEO_CARDS="radeon"

That two drivers installs fine, so i think is not problem in kernel .config.
But seems they dont work.

How i can solve that issuse.
Thank you.