Espero que você esteja usando uma versão assinada de 64 bits do driver de espelhamento. caso contrário, não há como o driver funcionar no Windows 7 x64. Se o driver tiver 32 bits, você ainda terá a sorte de poder inicializar o Windows.
De qualquer forma, aqui está uma citação de DemoForge Mirage Driver e TightVNC 2.0: Como usar?
There are two major problems with DFMirage:
It's a third-party driver, we do not own its code, we do not control its development and its license is not suitable for us. It's just not quite compatible with development and business models of our company.
Its future is indefinite. Windows Vista and Windows 7 seem to migrate to new rendering architecture which is not compatible with mirror drivers. It's not clear if it's worth to invest in a technology that may become obsolete in next versions of Windows.
I'd like to thank DFMirage developers, they've made a great work on the driver and helped the TightVNC project a lot by providing DFMirage to TightVNC users. However, we are not sure yet if it can be accepted for TightVNC 2.0.
I think we'll be able to make TightVNC version 2 very efficient even without the driver. Note that TightVNC 2.0 easily shares an Aero desktop which is absolutely impossible while using mirror drivers.
Note that this issue is still under consideration, we have not made a final decision yet.
Isso parece dizer que há um problema geral com o uso de drivers de espelho em versões posteriores do Windows, então o problema pode ser simplesmente que o DemoForge Mirage Driver é agora incompatível com o Windows.