OpenCV Error

05-23 17:18:06.026: E/BufferQueue(11428): [unnamed-11428-1] dequeueBuffer: min undequeued buffer count (2) exceeded (dequeued=5 undequeudCount=1)
05-23 17:18:06.076: I/Choreographer(11428): Skipped 84 frames!  The application may be doing too much work on its main thread.
05-23 17:18:06.116: D/JavaCameraView(11428): Preview Frame received. Frame size: 152064
05-23 17:18:06.146: D/JavaCameraView(11428): Preview Frame received. Frame size: 152064
05-23 17:18:06.156: E/cv::error()(11428): OpenCV Error: Assertion failed ((npoints = prevPtsMat.checkVector(2, CV_32F, true)) >= 0) in void cv::calcOpticalFlowPyrLK(cv::InputArray, cv::InputArray, cv::InputArray, cv::InputOutputArray, cv::OutputArray, cv::OutputArray, cv::Size, int, cv::TermCriteria, int, double), file /home/reports/ci/slave_desktop/50-SDK/opencv/modules/video/src/lkpyramid.cpp, line 845
05-23 17:18:06.156: E/org.opencv.video(11428): video::calcOpticalFlowPyrLK_12() caught cv::Exception: /home/reports/ci/slave_desktop/50-SDK/opencv/modules/video/src/lkpyramid.cpp:845: error: (-215) (npoints = prevPtsMat.checkVector(2, CV_32F, true)) >= 0 in function void cv::calcOpticalFlowPyrLK(cv::InputArray, cv::InputArray, cv::InputArray, cv::InputOutputArray, cv::OutputArray, cv::OutputArray, cv::Size, int, cv::TermCriteria, int, double)
05-23 17:18:06.156: W/dalvikvm(11428): threadid=11: thread exiting with uncaught exception (group=0x417afda0)
05-23 17:18:06.156: E/AndroidRuntime(11428): FATAL EXCEPTION: Thread-7944
05-23 17:18:06.156: E/AndroidRuntime(11428): Process: com.mukcay.cvtest, PID: 11428
05-23 17:18:06.156: E/AndroidRuntime(11428): CvException [org.opencv.core.CvException: cv::Exception: /home/reports/ci/slave_desktop/50-SDK/opencv/modules/video/src/lkpyramid.cpp:845: error: (-215) (npoints = prevPtsMat.checkVector(2, CV_32F, true)) >= 0 in function void cv::calcOpticalFlowPyrLK(cv::InputArray, cv::InputArray, cv::InputArray, cv::InputOutputArray, cv::OutputArray, cv::OutputArray, cv::Size, int, cv::TermCriteria, int, double)
05-23 17:18:06.156: E/AndroidRuntime(11428): ]
05-23 17:18:06.156: E/AndroidRuntime(11428):    at org.opencv.video.Video.calcOpticalFlowPyrLK_2(Native Method)
05-23 17:18:06.156: E/AndroidRuntime(11428):    at org.opencv.video.Video.calcOpticalFlowPyrLK(Video.java:501)
05-23 17:18:06.156: E/AndroidRuntime(11428):    at com.mukcay.cvtest.MainActivity.onCameraFrame(MainActivity.java:217)
05-23 17:18:06.156: E/AndroidRuntime(11428):    at org.opencv.android.CameraBridgeViewBase.deliverAndDrawFrame(CameraBridgeViewBase.java:387)
05-23 17:18:06.156: E/AndroidRuntime(11428):    at org.opencv.android.JavaCameraView$CameraWorker.run(JavaCameraView.java:328)
05-23 17:18:06.156: E/AndroidRuntime(11428):    at java.lang.Thread.run(Thread.java:841)