Frequently when I'm working in the Drawings & Layouts panel I duplicate existing layouts. When the dialogue box pops up with "Null" showing in the layout name field it means the app is about to crash. I cancel out, save, and close everything and quit and reboot, if the app doesn't crash first, which it usually does. This is a reqular problem with Autocad 2011 for Mac as well. Anybody experienced this? Anybody have a solution?