ar_track_alvar errors when I move ar tags in view of Kinect camera

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Hi, When I move the tags in the view of my Kinect camera, the following errors show up, saying it cannot detect anything, is there anyone have same problem? the error msg is like this:

[pcl::RandomSampleConsensus::computeModel] No samples could be selected!
[pcl::SACSegmentation::segment] Error segmenting the model! No solution found.
[pcl::SampleConsensusModel::getSamples] Can not select 0 unique points out of 0!
[pcl::RandomSampleConsensus::computeModel] No samples could be selected!

This is how I use this pkg:

roscore
roslaunch freenect_launch freenect.launch
rosrun ar_track_alvar individualMarkers 4.4 0.08 0.2 /camera/depth_registered/points /camera/rgb/camera_info /camera_link

and when I move the tags into the view of Kinect, the above error shows up. I really appreciate that if someone could help me fix this!