Using Blackdot marker get stucked in endless loop

When computing the trajectories of the test case for the blackdot marker PeTrack gets stuck in an endless loop in recoognition.cpp:573-597:

subGray.create(Size(subImg.rows,subImg.cols),CV_8UC1);
// liefert sehr dunkle bilder insbesondere bei rottoenen
//cvCvtColor(subImg, subGray, CV_BGR2GRAY);
// gewichtete umwandlung RGB nach Grey
dataImg = ((unsigned char*) subImg.data);
yDataImg = dataImg;
data = ((unsigned char*) subGray.data);
yData = data;
scaleR = midHue.redF(); scaleG = midHue.greenF(); scaleB = midHue.blueF();
scaleSum = scaleR+scaleG+scaleB;
scaleR/=scaleSum; scaleG/=scaleSum; scaleB/=scaleSum;

for (int y = 0; y < subGray.rows; ++y)
{
    for (int x = 0; x < subGray.cols; ++x)
    {
        dd = scaleB*dataImg[0]+scaleG*dataImg[1]+scaleR*dataImg[2];
        *data = dd<256?dd:255;

        ++data;
        dataImg+=3;
    }
    data = (yData += subGray.cols/sizeof(char)); //width);
    dataImg = (yDataImg += subImg.cols/sizeof(char)); //width);
}