Error loading DLL in python, not a valid win32 application [duplicate]
As the comments suggest, it could be an architecture problem.
If you're using a 32bit DLL with 64bit Python, or vice-versa, then you'll probably get errors.
Since I've had your error before, I recommend trying to load your DLL with 32bit Python.
One way to test if a *.dll-file is 32bit or 64bit, is to use dumpbin.exe, e.g.
dumpbin /headers dsusb.dll...FILE HEADER VALUES 14C machine (x86)...machine (x86) means 32bit, machine (x64) means 64bit.