I did as advised (recompiling C code with -arch i386) and at least I now get a new error message when I run analysis: Error, cannot import core CCPN Python modules: Maybe your PYTHONPATH environment variable is not set or does not contain the current CCPN installation directory. Traceback (most recent call last): File "/Users/mp84/Work/ccpnmr/ccpnmr2.1/python/ccpnmr/analysis/AnalysisGui.py", line 71, in <module> raise ImportError ImportError I started AnalysisGui.py both with the ccpn version as well as the system copy of python, the result is the same. There is also no improvement when I set PYTHONPATH to the python2.5 directory that comes with CCPN. Any more suggesetions? thanks, mark