Getting weird fractal dimensions using FracLac

I am trying to determine fractal dimensions of various images and noticed I was getting different values than images that already had the fractal dimension calculated. I am using the standard setting for box count settings. For example, I tried calculating the fractal dimension of a straight line, which should be 1, and I got 0.77. Did anyone else have this problem?

http://www.polyvore.com/cgi/img-thing?.out=jpg&size=l&tid=4219540