If I recall correctly I saw the same problem on this forum. Overwriting this file should help.
My files from C:\Windows\System32
Are your files from the same directory?
It looks like you don't have Service Pack 1 installed (If yes install it).
Here is my D3DX9_43.dll from C:\Windows\System32
Before changing it backup your original files.
D3DX9_43.zip