Ok, so the only thing I can think of which may cause this effect is if audio was being played at a certain sample rate, but you were recording it at a different sample rate. SoundTap should handle the matching of sample rates for you, but for some reason in your case it seems like it isn't.
Things to check:
1. Have you changed any of the advanced settings of your audio card to use a different sample rate? If so, try setting them back to default.
2. Open SoundTap's settings dialog and try recording to a different format. eg. If you are recording to mp3, try recording to .wav.
3. Reboot your computer and make sure that you start SoundTap *before* you open your web browser.
Let me know if any of this helps. If not, we'll try and troubleshoot things a bit further.
Regards,
Ben