OK, I get it.
A module name is (case sensitive) the name of the source .py module, not a compiled dll.
, myClass.py, MyClass.dll, ImportModule("myClass") not ImportModule("myClass")
EDIT:
:
import clr
clr.CompileModules("CompiledScript.dll", "script.py")
, pyc.py, dll __main__ .py.
...
IIRC, python __main__, (.. ), ...