I just recently installed OBGE and obse v20 and every time I try to launce Oblivion it says

The program can't start because d3dx9.dll is missing from the system.

Some support would be appreciated, plus I haven't found this problem on the OBGE forum page yet.

Install DirectX 9.0c
If you are on Windows 7 with buit-in DirectX 11 and think that it is compatible downwards with version 9.... no, it isn't. Microsoft removed it from newer windows version, you must download and install it manually.