Also, make sure your playback software is configured to use the appropriate WT2496 drivers, depending on how you're using the soundcard. For example, if I'm running digi-out, I must make sure Foobar's set to playback via the WT2496 digi-out, i.e. Waveterminal 2496 (D).
Edit to add: depending on the s/w you're using, you may need to perform the config in the s/w proper, but may also need to do it in the Windows Sounds applet, for Win2k: Start | Settings | Control Panel | Sounds and Multimedia.