Bottom camera problem

Hi, I use gazebo 2.2 with ROS package tum_simulator. This is a package with simulator of quadrotor AR Parrot Drone. I had thought that bottom camera is not working and only front camera is OK, but I noticed that image from bottom camera don't display ground but sky. (strange) Please check this screen: http://snag.gy/L5Riw.jpg This is a world from Gazebo and two windows from rviz. Left image is a view from bottom camera :( and right image is a view from front camera. Black shape near window of the house is quadrotors' model. Have you ever heard abut this problem? Any ideas? I notice that when I run this node I got some errors, I hope that this is a reason of problems with camera. Error [SDF.cc:788] Missing element description for [offset] Error [SDF.cc:788] Missing element description for [drift] Error [SDF.cc:788] Missing element description for [driftFrequency] [ INFO] [1415319050.065958118, 659.736000000]: Camera Plugin (ns = /) , set to "" [ INFO] [1415319050.244706409, 659.736000000]: Camera Plugin (ns = /) , set to "" Error [SDF.cc:788] Missing element description for [accelOffset] Error [SDF.cc:788] Missing element description for [accelDriftFrequency] Error [SDF.cc:788] Missing element description for [rateOffset] Error [SDF.cc:788] Missing element description for [rateDriftFrequency] Error [SDF.cc:788] Missing element description for [headingOffset] Error [SDF.cc:788] Missing element description for [headingDriftFrequency] Error [SDF.cc:788] Missing element description for [driftFrequency] Error [SDF.cc:788] Missing element description for [driftFrequency] Error [SDF.cc:788] Missing element description for [offset] Error [SDF.cc:788] Missing element description for [driftFrequency] Error [SDF.cc:788] Missing element description for [velocityOffset] Error [SDF.cc:788] Missing element description for [velocityDriftFrequency] [ INFO] [1415319050.590175130, 659.736000000]: Using imu information on topic ardrone/imu as source of orientation and angular velocity. Please help.