Python calling C with callback to Python - crash!

[Will G.]

I know I'm rather demented to write something like this:
A.py calls B.dll using dynwin (windll)
B.dll has a callback to C.py and potentially calling it repeatedly.

When I run A.py, the callback is successfully called until it's last
invocation when "bam!!" python.exe crashes spectacularly.

I know the problem is on Python's side because when I use a C program
to invoke the B.dll, the callback to C.py is called and executed
flawlessly.

Appreciate any help!

Will G.

PS:
Here's the callback code, it's adapted (almost verbatim) from the
python on embedding doc:
    Py_Initialize();
    pName = PyString_FromString(HCFAMGR_MODULE);
    /* Error checking of pName left out */

    pModule = PyImport_Import(pName);
    if (pModule != NULL) 
    {
        pDict = PyModule_GetDict(pModule);
        /* pDict is a borrowed reference */

        pFunc = PyDict_GetItemString(pDict, PYTHON_FUNCTION);
        /* pFun: Borrowed reference */

        if (pFunc && PyCallable_Check(pFunc)) 
        {
            // WG - Specify the number of parameter we're going to
pass to this
            // function
            pArgs = PyTuple_New(4);

            // WG - Set the main claim as first argument (LPTSTR)
            pValue = PyString_FromString(charptrToHCFA);
            if (!pValue)
                fprintf(stderr, "Can't pass claim\n");
            PyTuple_SetItem(pArgs, 0, pValue);
            
            ... (finish assigning the parameters)

            // WG - Call the Python function
            pValue = PyObject_CallObject(pFunc, pArgs);
            if (pValue != NULL) 
            {
                result = PyInt_AsLong(pValue);
                Py_DECREF(pValue);
            }
            else 
            {
                PyErr_Print();
                fprintf(stderr,"Call failed\n");
                return 1;
            }
            Py_DECREF(pArgs);
            /* pDict and pFunc are borrowed and must not be
Py_DECREF-ed */

        }
        else 
        {
            PyErr_Print();
            fprintf(stderr, "Cannot find function \"%s\"\n",
PYTHON_FUNCTION);
        }
        Py_DECREF(pModule);
    }
    else 
    {
        PyErr_Print();
        fprintf(stderr, "Failed to load \"%s\"\n", HCFAMGR_MODULE);
        return 1;
    }
    Py_DECREF(pName);
    Py_Finalize();