How to solve "Catastrophic failure"

I get a

Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))

during use method of lobject.dll which was referred on my project.

UnityApplication giris = new UnityObjects.UnityApplication(); ***instance from .dll***

if (giris.Connect()) // ***this line is throwing that error***
{

}