Can't save
 

I have the newest version of Pro, and whenever I try to save one of my files, it works the first time and I choose a name for it... That is all good. However, when I save it again (even if right after) it says that it can't be saved. I moved Graffle over from my 2006 macbook running snow leopard to my new mac mini... Could that have anything to do with it? As of right now, I'm just making a bunch of different copies of my Graffles. Quick help would be appreciated as I am using this to make my formula sheets for my exams over the next few days! Thanks!