Help me urgently please!

Hello,
I have a question, and if possible would love someone to help me.
I can not play Cross Fire, I think I did everything right!, But when I click to open my Cross Fire acarece the following:
This application can not be started because it was found d3dx9_29.dll.A resettlement can fix the problem.
Well okay, you know, I reinstalled a good ai has the same thing, well you know i have very bothering would not be able to play cross fire, a friend asked me to go through msn and gave the same thing: /

Does anyone here could help me please, I really want to play!

Thank you.

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