Following a tutorial (can't post link) to write an tf listener for the frames openni_tracker publishes. Here is my listener:

  #!/usr/bin/python
  from kinect import Kinect      
  kin = Kinect()
  for i in xrange(10):
  print i, kin.get_posture()

Here is the kinect class file:

 #!/usr/bin/python
import roslib
roslib.load_manifest('kinect_listener')
import rospy
import tf

BASE_FRAME = '/openni_depth_frame'
FRAMES = [
'head',
'neck',
'torso',
'left_shoulder',
'left_elbow',
'left_hand',
'left_hip',
'left_knee',
'left_foot',
'right_shoulder',
'right_elbow',
'right_hand',
'right_hip',
'right_knee',
'right_foot',
  ]
 rospy.Duration()


 class Kinect:
 def __init__(self, name='kinect_listener', user=1):
 rospy.init_node(name, anonymous=True)
 self.listener = tf.TransformListener()
 self.user = user

 def get_posture(self):

 #try:
      frames = []
      for frame in FRAMES:
          trans, rot = self.listener.lookupTransform(BASE_FRAME,
                  "/%s_%d" % (frame, self.user), LAST)
          frames.append((trans, rot))
      return frames
      #except (tf.LookupException,
      #        tf.ConnectivityException,
      #        tf.ExtrapolationException):
    #    raise IndexError

When I run this I get this error:

Traceback (most recent call last):
File "/home/robotlab/catkin_ws/src/kinect_listener/src/kinect_listener.py", line 8, in <module>
print i, kin.get_posture()
File "/home/robotlab/catkin_ws/src/kinect_listener/src/kinect.py", line 49, in get_posture
"/%s_%d" % (frame, self.user), LAST)
tf.LookupException: Frame id /openni_depth_frame does not exist! Frames (1): 

Which doesn't make sense because when I run rostopic echo tf I can see the frame and the published transforms (for example):

frame_id: /openni_depth_frame
child_frame_id: /right_foot_1
transform: 
  translation: 
    x: 1.04582212435
    y: -0.372131748083
    z: -0.909085018278
  rotation: 
    x: 0.499999999997
    y: 0.500001836603
    z: 0.499999999997
    w: 0.499998163397

Why can rostopic see the frame fine but my code cannot? I already did the Psi pose in front of the kinect when I ran openni_tracker.