You're asking the wrong question.
The fact that these two pieces happen to be written in ATL to use COM simply means that you can't recompile them and use them as-is on Linux. As you know, the ATL template library is exclusively a Microsoft product and, AFAIK, needs Visual Studio to write. As you also know, COM isn't just a protocol (IUnknown, AddRef (), Release(), etc etc). It also requires library support (CoCreateInstance (), etc) at build time, and extensive runtime support (the registry, for example) in order to execute.
In short, both ATL and COM are pretty non-portable outside of Windows.
Does that mean you give up?
No. You need to ask what this component *does*. The fact that it's ATL and COM are just *implementation details*. You need to understand the actual requirements.
And I'm sure you'll find a *wealth* of possible solutions to choose from under Linux.
Good luck .. PSM
As you also know, COM and ATL are themselves obsolete. Microsoft is actively telling everybody to re-write the world ... only this time, to do it in C# or VB.Net... Keep those MSDN subscription dollars rolling, folks!