this has happened to me a few times. the problem is that one of your staralignment process icons is corrupt. the only way to find it is to start deleting them one by one and then try to save the project... warning though - once i tried to get fancy and load each SA icon into SA and then save a new process icon, in an effort to not lose my SA process icons. however when i hit the bad one, trying to save the new process icon caused PI to crash.
so to be safe, just delete the SA icons and try to save the project...
rob