[kwfinken]

We are having the same problems and error, the sensor is not showing any distance changes but is staying at 0. The error appears on the driver's station diagnostic tab.
==================ERROR====================
Assertion Failed: "m_downSource!=NULL" in clearDownSource() in c:/windriver/workspace/wpilib/counter.cpp at line 337.

================Source Code=================

#include "WPILib.h"

DriverStationLCD *dsLCD = DriverStationLCD::GetInstance();

class ArmyOfSumRobot : public IterativeRobot
{
/*Initialize interaction with Hardware*/
RobotDrive *MyRobot; //Robot Drive
DriverStation *Ds; //Driver Station

Ultrasonic *USleft;

public:

ArmyOfSumRobot(void)
{
Ds = DriverStation::GetInstance();

MyRobot = new RobotDrive(1,2,3,4);// create robot drive base with 4 motors

USleft = new Ultrasonic(4,5); // create ultra sonic on digital IO 4,5 in inches
}

void AutonomousContinuous(void)
{
GetWatchdog().Feed();
}
void TeleopContinuous(void)
{
GetWatchdog().Feed();

dsLCD->Printf(DriverStationLCD::kUser_Line1, 1, "ultra sonic left: %g", USleft->GetRangeInches());
}

void DisabledPeriodic(void)
{
GetWatchdog().Feed(); // feed the user watchdog at every period when disabled
}

void TeleopPeriodic(void)
{
GetWatchdog().Feed(); // feed the user watchdog at every period when in autonomous

}

void DisabledContinuous(void)
{
GetWatchdog().Feed(); //do nothing
}

void AutonomousPeriodic(void)
{
GetWatchdog().Feed(); //do nothing
}
/********************************** Init Routines *************************************/
void DisabledInit(void)
{
}

void AutonomousInit(void)
{
}

void TeleopInit(void)
{
}

void RobotInit(void)
{

//initialize ultrasonics
USleft->SetDistanceUnits(Ultrasonic::kInches);
USleft->SetAutomaticMode(TRUE);


}
};

START_ROBOT_CLASS(ArmyOfSumRobot);