I had similar symptoms with my OSX Lion machine and macports-built
dependencies. In my case, I was using the macports Python 2.6, but
pmt_swig.so was linked against the OSX-provided Python 2.7 library,
unlike everything else which was properly linked against the /opt/local
macports python 2.6.
I'm interested in demodulating the simple PPM signal commonly used for
RC aircraft control in the 72 MHz band. While searching, I came across
a post to this list back in 2005 where Chuck Swiger linked to a page
that looked interesting, but the page isn't up and archive.org doesn't
go that deep.
D