When I run this program under windows XP, it works fine for a short while and then it uses 100% processing and stops working. The diagram in question is not very complicated, containing just two classes and one package (at the moment). I have yet to identify what is causing this.
Same issue on Vista. I can get the program to save the output file, and when I attempt to reopen the file, it still crashes. I can provide this file to anyone who wants it, my email is [ben harris 5 at aol dot com], just put TinyUML in the subject line.