Python error - psycopg2: no appropriate 64-bit architecture?!

Question

I'm running Mac OSX. Until today I had Python 2.6 with psycopg2 running just fine, I was using it with Django and Pylons. I've just reintalled postgres (I don't know if this is connected) and suddenly I can't import psycopg2 into Python without a strange error:

>>> import psycopg2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "build/bdist.macosx-10.6-universal/egg/psycopg2/__init__.py", line 69, in <module>
  File "build/bdist.macosx-10.6-universal/egg/psycopg2/_psycopg.py", line 7, in <module>
  File "build/bdist.macosx-10.6-universal/egg/psycopg2/_psycopg.py", line 6, in __bootstrap__
ImportError: /usr/lib/libpq.5.dylib: no appropriate 64-bit architecture (see "man python" for running in 32-bit mode)

Trying with Python 2.5 gives a similar error:

>>> import psycopg2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/lib/python2.5/site-packages/psycopg2/__init__.py", line 69, in <module>
    from _psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
ImportError: dlopen(/opt/local/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/psycopg2/_psycopg.so, 2): Library not loaded: /opt/local/lib/postgresql84/libpq.5.dylib
  Referenced from: /opt/local/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/psycopg2/_psycopg.so
  Reason: no suitable image found.  Did find:
        /usr/lib/libpq.5.dylib: no matching architecture in universal wrapper

I have no idea what this means, where it's come from, or what to do about it. Please can anyone help?

Answer 1

Have you just upgraded to Snow Leopard by any chance? The Leopard version of Python is 32-bit, while the 64-bit is in Snow Leopard. It breaks some libraries that use native code that aren't available in 64-bit mode.