[R2K2D2]

This is what you should do...at the bottom left is a tree system that shows all the components and what constraints have been placed on it. Expand the branches that you are trying to constrain together. Then, go through and delete any random constraints that you do not know why they are there. Then try it again. Often times what happens is a user will put a constraint that either they forgot they put or that didn't fully work. Then, they try to apply another constraint and it just does not work, giving you an error. Try this approach, and if it doesn't work, post with more questions.