This is similar to http://www.graphviz.org/bugs/b791.html in that if you comment out the rankdir=RL then it doesn't blow up, but this still blows up with the fix for 791 in place (I assume that 791 is fixed in 2.7.x).
[erg] This is yet another stack overflow on Windows. gdFillImage is written recursively and the given image is 690 by 40590. So for the first row (x=0) we get the stack gdImageFill(0,40590), gdImageFill(0,40589), gdImageFill(0,40588),...
Input file: b826.dot