I've found the problem. Sorry to cause a fuss!
A package that I have created provides a copy of argparse that doesn't have a __version__ attribute. Should Ipython be able to work around this or do I need to change something in my installation scripts, do you think? This is my setup.py: import sys import imp from setuptools import setup # Default list of provided packages. packlist = [ 'morebasemap', 'morebasemap.scripts','decimaldegrees', 'pyasc', 'appdirs' ] # Try for argparse and if it's not there provide as package try: imp.find_module('argparse', sys.path[1:]) except ImportError: packlist.append('argparse') setup( name='morebasemap', version='0.09', include_package_data = True, packages=packlist, requires=[ 'matplotlib', 'basemap', 'netCDF4' ], package_dir={ 'morebasemap': 'morebasemap', 'morebasemap.scripts': 'scripts'}, package_data={'morebasemap': ['json/*.json']}, entry_points = { 'console_scripts': ['bathy2xyz = morebasemap.scripts.bathy2xyz:main'] } )