Thanks for that wildbill. I have found that with many microcontrollers, even with internal pull-up R's, with un-avoidable long leads on pins, it can be a problem, cured only by the lowest value resistor that will still permit a valid difference between 0 and 1! I've been involved in electronics all my life but NOT programming!
Steve
http://www.calvertonweather.co.uk
http://www.aroundinten.org