do you have SWDM licentie key for at least sw 2015 ?
Thanks comment Ivana.
Yes, I have license 2015.
Maybe It is not license problem because that is return error(5)(I experience this problem already )
I found that are running same method(getDocument) succesful from another class.
So i compare what is different. and I solved this problem.
I remember it was pixed when i change path's type(LPCTSTR -> CString).
So i commented here yesterday.
But maybe that is not reason. so i deleted my comment.
I tried to find true reason. but i couldn't.
Anyway I solved problem. but i am sorry that i can't give solution and reason about this problem to you.