DSound error message

[shniglebop]

I downloaded the 32 bit build of Dolphin recommended in the "Dolphin Complete Setup Guide" thread (http://forums.dolphin-emu.org/thread-3533.html) from Unknownforce's signature (http://unknownforce.selfip.com/), and followed all the steps to set it up, but when I try to play The Legend of Zelda: Four Swords Adventures, I get an error message that reads "Could not initialize backend DSound, falling back to NULL", followed by "Sound backend DSound is not valid, falling back to NULL", which is then followed by "Error starting up sound stream", and then Dolphin quits. The first time I downloaded it and set it up, it worked fine, except for the game running back and forth from half speed to normal speed. After reading the forums, I thought it might be the copy of the game that was causing the slow-down, so I downloaded a different copy, and tried that, which caused this current problem. I deleted the second copy, as well as the first copy of Dolphin (I tried with the original copy of the game, but to no avail), and re-downloaded it and set it up again, exactly the same way, but the error message still comes up when I try to play the first version of the game (the one that worked, but was slow). What should I do?