Motors not reacting to Ultrasonic Sensor

I am relatively new to the NXT Mindstorms and I am a mentor for the local grade school Mindstorms for our company. I am building the basic maze robot. I know that my Ultrasonic sensor is working and the motors are working but the bot does not respond to the ultrasonic. When the bot gets close to the wall it should turn away but it just runs into the wall instead. Can anyone tell me what part of my programming is wrong.

It starts with the loop set to infinity. Within the loop is the Ultrasonic sensor on slot 4 set to 4 inches. Within is the swith with motors to move to or away from the wall.