"dlopen: no suitable image found" in Mercurial

I've got a nasty feeling this is something to do with using 32-bit Python and/or 64-bit Mercurial, but I'm new to Macs and I don't fully understand the background.

I'm running Django and I've got Mercurial and Python 2.6 installed (in both cases, the default versions from Macports). I've set 32-bit Python as an environment variable:

export VERSIONER_PYTHON_PREFER_32_BIT=yes

since without it, Mercurial refused to run and said "no suitable 64-bit architecture".

When I try to run Django (or Mercurial) I get

ImportError at /
dlopen(/lib/python2.6/site-packages/mercurial/osutil.so, 2): no suitable image found.  Did find:
    /lib/python2.6/site-packages/mercurial/osutil.so: no matching architecture in universal wrapper

Google isn't much help here. What's going on? Should I reinstall a different version of Mercurial, and if so, what exactly do I need?

Tha开发者_开发问答nks in advance. Very puzzled.