You cant' cross rivers, and you get stuck on certain cliffs (the deep black lines). Make sure you aren't using eye-candy for one, and then secondly it's possible if you try to move parallel to the river (or what you're stuck on) you might be in crescent shaped pocket and just can't tell so the only way you would be able to move is directly away from the river.
Try moving away from the river and taking a bridge across. I guarantee you're stuck because of where you're trying to go, not because there's something broken with your guy or area.