Using COM. Please help.

[Andrej Mitrovic]

You mean COM interfaces? I usually do this:

interface SomeComInterface : IUnknown
{
    extern(Windows):
    BOOL PrototypeFoo();
}

But maybe this is already implicit when deriving from IUnknown, I wouldn't know.

But from what I can tell some of those prototypes seem to have C
linkage, maybe you're getting access violations due to wrong calling
conventions.