Testa det här, funkade för mig: (Saxat från EA´s eget forum.)
1. Goto: the games installation directory and find the directx installation folder. For me it is as follows.
C:\Program Files (x86)\Electronic Arts\Battlefield 3\__Installer\directx\redist
2. Created a new folder inside the above path. I called mine "original" but it does not matter what you call it.
3 Cut all of the files out of the \directx\redist folder to the new folder you created. But LEAVE THE DSETUP.DLL, DSETUP32.DLL AND DXSETUP.EXE WHERE THEY ARE.
4. Run the installation again.