I've tried re-extracting it but WinRAR says the archive is corrupt even though it appears to extract it fully.
I'm not really keen on the idea of downloading the 15GB file again, is the corruption likely to be the issue?
This is why I am waiting for Steam to have this deal again - so much easier, plus auto updates.
Is it possible to try and install the game by mounting it on virtual drive? Also anyone tried contacting the D2D support?