Hi, thanks for msg me. It's so easy. Ok, this is the steps that i've done :
1) I've download the Direct X 9.0b from http://www.superfoxs.com and uninstall the Direct X 9.0b. (If this way not work, you just click >Start >Run and type : regedit >OK and double -click on HKEY_LOCAL_MACHINE and then double -click SOFTWARE > Microsoft > DirectX. You should right click on this folder and delete it).
2) Then you should have DirectX 9.0c installer. Get the 2 dll files from the previous nasheet's msg (DSETUP.dll and d32setup.dll) and replace to DirectX 9.0c installer (make sure you replace it) and finally install it normally.
3) Finally, click >Start >Run> dxdiag and BINGO! Its done!
(I'm sorry because i'm not fluently in English)