Could you try searching for OpenAL32.dll and OpenAL64.dll on your harddrive, and then removing any copies that are somewhere under the windows/ directory?
If there are other copies as well that are provided by some other software, you'd want to make sure that software isn't running (and doesn't start on boot), and then reboot. This looks like an issue caused by the wrong version of the OpenAL dll being picked up by the game (despite it specifying which one to use; windows is a bit funny like that sometimes), so cleaning up other versions that are on your system may/should help.
Actually, doing a reboot first, and then trying to run the game, might not hurt either.