The drivers you have installed were the first release Vista drivers and are garbage, if anything you want to use the latest drivers that were released last month (which are working just fine opn my Audigy 4). Alternatively you can also give the daniel_k driver set a try,
SBAX_PCDVT_LB_2_15_0004EQ.rar - FileFront.com
which will also allow you to use some of the apps as well.