Trouble following Lego NXT tutorials

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I've been trying to get ROS-NXT to work with my Lego NXT. In the past, I've successfuly been able to write programs in NXT-Python in order to control the robot. However, this is my first experience with ROS.

I've read the docs for ROS, and tried to follow to the tutorials for ROS-NXT. I can reproducibly get the touch sensor demo to work. However, I just cannot get the teleop demo working. Do you know if this example is in working condition? Any ideas what is going on? I know that my keystrokes are being recieved by the program (I modified the code to double check the keystrokes were being received). I also tried removing the gyroscope sensor from robot.yaml before I launch nxt_robot_sensor_car (since I don't have one).

I'm on Ubuntu 10.10. My NXT has the correct firmware (1.28). As I said, I can get the robot to move around using NXT-Python but have had no luck with ROS-NXT so far.

Any help you can provide would be much appreciated!

Sample errors I see from the terminal where I launched nxt_robot_sensor_car:

[WARN] [WallTime: 1300631066.685828] l_wheel_joint not reaching
desired frequency: actual 1.132604, desired 20.000000
[WARN] [WallTime: 1300631066.686174] m_wheel_joint not reaching
desired frequency: actual 0.575387, desired 1.000000
[WARN] [WallTime: 1300631066.686410] ultrasonic_sensor not reaching
desired frequency: actual 0.982331, desired 5.000000
[WARN] [WallTime: 1300631066.686641] color_sensor not reaching desired
frequency: actual 1.077575, desired 10.000000
[WARN] [WallTime: 1300631066.697589] r_wheel_joint not reaching
desired frequency: actual 8.055285, desired 20.000000
[WARN] [WallTime: 1300631066.803811] l_wheel_joint not reaching
desired frequency: actual 1.117669, desired 20.000000
[WARN] [WallTime: 1300631066.804158] m_wheel_joint not reaching
desired frequency: actual 0.571507, desired 1.000000
[WARN] [WallTime: 1300631066.804392] ultrasonic_sensor not reaching
desired frequency: actual 0.971076, desired 5.000000
[WARN] [WallTime: 1300631066.804623] color_sensor not reaching desired
frequency: actual 1.064048, desired 10.000000
[WARN] [WallTime: 1300631066.819145] r_wheel_joint not reaching
desired frequency: actual 8.072015, desired 20.000000
[ERROR] [WallTime: 1300631066.895515] bad callback: <bound method
BaseController.jnt_state_cb of <__main__.BaseController instance at
0x9a0e4ac>>
Traceback (most recent call last):
 File "/opt/ros/diamondback/stacks/ros_comm/clients/rospy/src/rospy/topics.py",
line 563, in _invoke_callback
   cb(msg)
 File "/opt/ros/diamondback/stacks/nxt/nxt_controllers/scripts/base_controller.py",
line 78, in jnt_state_cb
   self.vel_trans = 0.5*self.vel_trans + 0.5*(velocity[self.r_joint]
+ velocity[self.l_joint])*self.wheel_radius/2.0
KeyError: 'l_wheel_joint'

[ERROR] [WallTime: 1300631066.896057] bad callback: <bound method
BaseOdometry.jnt_state_cb of <__main__.BaseOdometry instance at
0x91efa2c>>
Traceback (most recent call last):
 File "/opt/ros/diamondback/stacks/ros_comm/clients/rospy/src/rospy/topics.py",
line 563, in _invoke_callback
   cb(msg)
 File "/opt/ros/diamondback/stacks/nxt/nxt_controllers/scripts/base_odometry.py",
line 80, in jnt_state_cb
   self.l_pos = position[self.l_joint]
KeyError: 'l_wheel_joint'