System.Runtime.InteropServices.ComException [0x80004005] thrown

I have two projects in same visual studio solution. C# and C++/CLI. C++/CLI refers C# project. Both the project use a set of DLLs(given by some vendor). Among them one of the DLL is throwing this exception. When checked in metadata files of the DLL i can see the following difference between the DLL throwing the error and rest. Diff: Using System; and TypeLibType(TypeLibTypeFlags.FDual]

I am new to this .NET. Some help will be appreciated.