This could possibly be a conflict between Reason 1.0.1 and the SoundBlaster drivers. We are looking into it at the moment. Until we know more, this is the way to solve it:
1. Go to Control Panels -> Multimedia
2. In the Audio Playback pane, click ‘Advanced Options’.
3. Set the Audio Playback Hardware Acceleration to the ‘Basic acceleration’ mode.
4. Click Ok in the advanced settings and in the control panel.