Logged In: YES 
user_id=21627

AFAICT, PYTHONPATH is *not* ignored when running a debug
build. If you think it is, please run the debug and the
nodebug interpreter (i.e. python.exe and python_d.exe), and
report the values of sys.path for either case.

More likely, the cause of your problems is that the import
code looks for different DLL name *in sys.path*. I.e. when
you do 
import foo
in a nodebug build, it will try to find foo.pyd or foo.dll.
In a debug build, it will try to find foo_d.pyd or
foo_d.dll. So if you only have foo.pyd, then importing foo
will fail if Python was compiled with _DEBUG. 

Again, this is by design: foo.pyd might crash the debug
interpreter, since the object layout is different.

If you merely want to single-step through the Python
runtime, without making use of the Py_DEBUG features, you
should build the release version of Python, but activate the
generation of debug symbols.