When pruning roses one sometimes needs to be a sort of detective, a rose detective if you will. Pruning is all about making the plant a manageable size, open for air circulation and getting rid of diseases. This little line-nub-thing, called a bud eye is where a leaf was. Sometimes it's difficult to see and you need to search for it. This is what you cut above because this is from where the new growth comes. You cut above a bud eye facing away from the center of the plant so that you have a clear center of the bush. A clear center equals good air circulation and deters diseases. You could just whack wherever and the plant would recover but would be happier if you cut above a bud eye :-)
I pruned 297 roses this week for a total of 536 so far. Enjoy your rose detective work!