turtlebot visualization tutorial : missing step ?

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I am a beginner with the turtlebot, and I am getting through the tutorial. Everything went smoothly until visualization : http://wiki.ros.org/turtlebot/Tutoria...

"roslaunching" 3dsensor.lauch results in :

[ INFO] [1469218497.427352736]: Initializing nodelet with 4 worker threads.
[ INFO] [1469218499.896268578]: Device "1d27/0601@1/32" found.
[ERROR] [1469218500.368594755]: Unsupported color video mode - Resolution: 640x480@30Hz Format: RGB888
[ INFO] [1469218501.848436029]: Starting depth stream.
[ INFO] [1469218502.347021890]: using default calibration URL
[ INFO] [1469218502.347443168]: camera calibration URL: file:///root/.ros/camera_info/rgb_PS1080_PrimeSense.yaml
[ INFO] [1469218502.348959188]: Unable to open camera calibration file [/root/.ros/camera_info/rgb_PS1080_PrimeSense.yaml]
[ WARN] [1469218502.349194447]: Camera calibration file /root/.ros/camera_info/rgb_PS1080_PrimeSense.yaml not found.
[ERROR] [1469218503.085167492]: Rectified topic '/camera/depth/image_rect_raw' requested but camera publishing '/camera/depth/camera_info' is uncalibrated
[ WARN] [1469218512.948623954]: [image_transport] Topics '/camera/depth/image_rect_raw' and '/camera/depth/camera_info' do not appear to be synchronized. In the last 10s:
    Image messages received:      0
    CameraInfo messages received: 300
    Synchronized pairs:           0

RViz starts correctly and shows the robot model and the tf tree. But nothing else. Status of Laserscan, DepthCloud,Registered Depth, PointCloud, Registered PointCloud are all "Ok". I checked the topic /camera/depth/image_raw and it was being broadcast at 30Hz. Yet, none if this is displayed.

The status of "Image" is "Warn" (no image received).

Looking for this I found that maybe this may be due to me not calibrating the xtion. ( http://wiki.ros.org/camera_calibration ). I am a little dubious because the tutorial does not mention this (or did I miss it ?). Also since the depth images are broadcasted, it seems strange they are not being displayed.

Anything I may be missing ?

(ubuntu 14.04, ros indigo, kobuki base, PrimeSense)