Trouble importing python module despite directory appearing in the path

Question

I'm trying to import a module into python but having difficulty.

I have defined the Environment Variable PYTHONPATH which contains C:\MyModules.

I get the following from Python 2.7 when I ask it about the path.

>>> import sys
>>> sys.path
['', 'C:\\MyModules', 'C:\\Python27\\python27.zip', 'C:\\Python27\\DLLs', 'C:\\Python27\\lib', 'C:\\Python27\\lib\\plat-win', 'C:\\Python27\\lib\\lib-tk', 'C:\\Python27', 'C:\\Python27\\lib\\site-packages']

C:\MyModules contains the module foo.pyd. I know foo.pyd is a working module because it works on other computers.

When I try to import foo, this happens:

>>> import foo
Traceback (most recent call last):
 File "<string>", line 1, in <fragment>
ImportError: DLL load failed: The specified module could not be found.

What are the possible reasons this might be happening?

• Russell Dias: You're most likely missing some third-party dependencies.
• Derek: As in foo.pyd depends on programs that I do not have installed on my computer?
• Russell Dias: Run it through: dependencywalker.com
• Derek: Thanks, this turned out to be the case. foo.pyd had a third party dependency that was missing. I've added the third party files and it now loads fine. My next question is naturally - Why did python tell me the module could not be found? Why didn't it tell me there was an error loading the module or something more helpful?
• Russell Dias: I've submitted it as an answer. Hope it helps.

Answer 1

You're missing a dependency, run it through Dependency Walker.

As for your question in the comments. I can only assume the module it was trying to import was written in C, which affected Python's backtrace.

Decided to submit this as an answer.

• Derek: Yes, it was written in C++, good guess! I am surprised then that Python doesn't complain that its backtrace didn't work correctly, or something along those lines. It left me wondering why python couldn't find the module.
• Glider: Don't confuse the python module with the module that is not found - which is the third party dependency module. foo.pyd is found correctly, but complains when loading that foo.pyd can't find the module it depends on.
• Derek: Okay, so DLL load failed: was saying that it found the DLL, but loading it failed? And The specified module was the one specified by the DLL, not the one specified by me when I said import foo? That makes more sense. Thanks.