I am unable to create a new library in version 6.4 running on OSX 10.8. The general procedure is
1. Open Eagle
2. File->New->Library
3. File->Save As
Then the entire program crashes. I have rebooted the machine, but haven't tried much else.
I was able to do this at least once before on this version, but I can only edit existing libraries.
Crash dump attached.