I have a Mac G4 PPC running OS X 10.3.9 on which previous versions of chimera have run without incident. I installed chimera-1.2509 of May 01, 2008 after removing the chimera-1.2492 of Feb 11, 2008 I had been using. However, when I attempted to run chimera-1.2509 it did not start and the following error messages were written to the console.log file accessible by console.app rather than to the X-terminal: Traceback (most recent call last): File "/Applications/Chimera.app/Contents/Resources/share/__main__.py", line 65, in <module> value = chimeraInit.init(sys.argv) File "/Applications/Chimera.app/Contents/Resources/share/chimeraInit.py", line 279, in init import chimera File "/Applications/Chimera.app/Contents/Resources/share/chimera/__init__.py", line 15, in <module> from _chimera import * ImportError: dynamic module does not define init function (init_chimera) This appears to be specific to the Mac OS X version as the Windows version of chimera-1.2509 works. Obviously, I removed chimera-1.2509 from the Mac and reinstalled chimera-1.2492 of Feb 11, 2008 which does work on this Mac. Sincerely, -- Bruce D. Ray, Ph.D. Associate Scientist, and Operations Director NMR Center IUPUI Physics Dept. 402 N. Blackford St. Indianapolis, IN 46202-3273