[Oromus]

Here's your problem:

public void robotInit() {
        ...stuff...
        ultra.setAutomaticMode(isEnabled()); <---
        ultra.setEnabled(isEnabled()); <---
        ...other stuff...
}

When robotInit is run, the robot is disabled. That means that isEnabled() will return false, which means your ultrasonic sensor is never turned on, along with automatic mode being set to false. I'd suggest just changing the lines to ultra.setEnabled(true) and ultra.setAutomaticMode(true).