CapSense library gets -2 when using wifi rev2

#include <CapacitiveSensor.h>
 * CapitiveSense Library Demo Sketch
 * Paul Badger 2008
 * Uses a high value resistor e.g. 10M between send pin and receive pin
 * Resistor effects sensitivity, experiment with values, 50K - 50M. Larger resistor values yield larger sensor values.
 * Receive pin is the sensor pin - try different amounts of foil/metal on this pin
CapacitiveSensor   cs_4_2 = CapacitiveSensor(2,3);          // 10M resistor between pins 4 & 8, pin 8 is sensor pin, add a wire and or foil
void setup()                    
   cs_4_2.set_CS_AutocaL_Millis(0xFFFFFFFF);     // turn off autocalibrate on channel 1 - just as an example
void loop()                    
    long start = millis();
    long total1 =  cs_4_2.capacitiveSensor(30); 
    Serial.print(millis() - start);        // check on performance in milliseconds
    Serial.print("\t");                    // tab character for debug windown spacing
    Serial.println(total1);                  // print sensor output 1
    delay(100);                             // arbitrary delay to limit data to serial port 

It works fine with a regular Uno. How is this even possible. Aren't these pins all doing the same thing?

Darn, I'd hoped this would save me from having to wire up a switch.

Anyone ever get it to work?