DSound error in windows XP 64 bit

[KHRZ]

I've been trying Dolphin with Windows XP 64 bit, however I encounter a problem that I couldn't find the solution to. I have the required runtime library and DX9 installed of course. When I boot a game, I get the error "Could not initialize backend DSound, falling back to NULL", then a similar message, "Sound backend DSound is not valid, falling back to NULL" then Dolphin closes. With Nullsound on, the games run brilliantly, except some are just in the upper left corner in full screen mode.

Note everything works perfect in Vista 32 bit (I have dualboot)

Specs: Core2Duo E8400 3,0 Ghz; 4Gb RAM; NVIDIA GeForce GTX 260; WinVista 32 Bit/WinXP 64 Bit