Had the same problem with a dll I was using, but managed to get it working by looking the the function names inside the DLL.
It seems as some C++ DLLs have mangled function names, I used dependancy walker to find the correct function names that worked. You can also see it in wordpad once you know what to look for.
i.e. the Function name
IdleTrackerInit
Turned into
?IdleTrackerInit@@YAHXZ
