I'm sorry I can't provide a fully-detailed report 
here, but I'm not in a position to be able to 
reproduce the problem.

In short, I installed the Universal build of Python 
2.4.3 for the Mac downloaded from:

http://pythonmac.org/packages/py24-fat/index.html

I don't know whether this is the same as the download 
from:

http://www.python.org/download/releases/2.4.3/

Once installed, I attempted to build ctypes.

The build failed due to an assembly error (unknown 
instruction). I'm not familiar with the PPC or x86 
assembler code so couldn't do a thorough analysis.

I needed Python2.4 to work, so I found an older 
PPC-only installer and used that.