installation problems on OSX Lion

Hi

I'm running OSX Lion and trying to install psycopg2 2.4.2 using PIP.
The installation finishes successfully. But then I get the following
error when trying to import:

Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05)
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import psycopg2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/psycopg2/__init__.py", line
67, in <module>
    from psycopg2._psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
ImportError: dlopen(/Library/Python/2.7/site-packages/psycopg2/_psycopg.so,
2): Symbol not found: _PQbackendPID
  Referenced from: /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
  Expected in: flat namespace
 in /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
>>>

Anybody know how to fix this?

  -Sean