SystemError:null argument to internal routine

[erik.wilsher at iname.com]

I'm developing a program using python and the metakit wrapper Mk4py.  
When running a large test case I get the error message:

SystemError:null argument to internal routine

The traceback indicates that this happens in a comparison operation 
between two floating point numbers in python.

-Is this a symptom of leaking ref-counts?
-How can I find out which object that is leaking?

    EW