I just got Empire at War: Forces of Corruption, installed it, and when I went to configure the audio it would not allow me to enable EAX! I don't know what the problem is here, because I have a Creative X-Fi sound card so it should work fine, right?

System specs:
Nvidia Geforce 7900 GT
Creative X-Fi sound card
Nforce 4 motherboard
Athlon 64 3700+ CPU
Windows XP Serviec Pack 2 (with all updates)

All drivers are up to date. I've tried all of the EAX options from EAX to EAX 4 and it wouldn't enable any of them. No viruses or adware is currently on my system. Can anybody help me?