Do you have the manual? I seem to remember there being a procedure for resetting the Whammy when this happens...it would appear to be a known issue easily fixed.
Unless it's something else in your case, of course.
EDIT: Just found the info, it's actually for recalibrating the treadle but I'm thinking you may have inadvertently put your Whammy into setup mode, so give this a go:
Calibrating the Treadle
In the unlikely event that the treadle pedal does not respond properly, or that the note does not
bend or return to the correct pitch, it may need to be recalibrated. The following steps outline
the procedure for treadle recalibration:
1. Disconnect the power from the WhammyTM pedal.
2. Press and hold the footswitch down while reconnecting the power. One of the preset LEDs
will blink indicating that you are in set up mode.
3. Rock the treadle fully forward (toe down) and fully back (toe up) two times.
4. Press the footswitch again to exit the set up mode.
This completes the treadle calibration procedure.