Whirpool will tell you otherwise, but I believe there is a defect in some models. My parents and I both own a whirlpool and both show this error every so often. To get out of this mode, do the following key sequence on the control panel.
Heat Dry - Normal - Heat Dry - Normal
Wait a few seconds and then hit cancel twice
We had a serviceman come out and spend a couple of hours trying to fix the problem until someone at whirlpool sent him a copy of the control pad command sequences. They say that the unit will go into this mode if the water coming in isn't hot enough. The sensor shuts down the cycle and locks up the dishwasher.
Brian, October 2006
