I ran into the same problem when I first installed it on one of my desk which has a SoundBlast 5.1 Live (pretty old audio card). After searched over creative.com and downloaded the driver from there, running setup.exe in the driver folder, it didn't seem to work as supposed. I opened the device manager and found windows 7 did detect the audio card but without a proper driver. I took the following steps to make it work.
Double click the unrecognized device and go to driver tab then click at driver update, choose to Browse my computer for driver software, browse to the directory where the driver located, locate the driver for Vista. Now you are set to install the driver. Hopefully this works for you as well. Good luck!