I am having trouble programming my ultrasonic sensor to make it sense anything in front of it.
I am using while ( Sensorvalue[Ultrasonic] < 2) then have it move in the while loop
However, when I point my robot to a wall that is really close to it (<1 inch). It doesn't seem to function.
What is the problem?. Please help.

Can you please post the entire code inside of [code] and [/code] tags? That'll help us diagnose a syntax or logic error.

This may also be an issue of the sensor being outside of its usable range. Sonar sensors have a maximum and minimum range that they will work properly within; if the object being detected is too far away, the echoes either won't reach the sonar receiver with enough strength to be detected, or will take too long to 'ping' back to the receiver. If the object is too close, the sound wave 'pings' back too quickly for the sonar sensor to read it.

Taking a look at the Ultrasonic Range Finder's product page on VEX's website, we see that the usable range for the sensor is "1.5 in to 115 in". Thus, moving an object any closer to the sensor than that may give unreliable results.