Hi,
are you sure the equation for calculating the resistance is correct? From the schematics in your code:
// Configuration:
// 5v------10k-------Sensor------GND
// |
// Analog
it should be:
float aread = 5.0 * (analogRead(0) / 1024.0) // voltage in Volts
float resistance = (10000 * aread) / (5.0 - aread); // resistance in ohm