Heartland

I'm sure it must be recoverable. I know C/C++ very well, but downloading the source code and working around it is a last option.

Anyone?

Are you sure the flac file is complete/intact? If it's a torrent and you're yet to finish downloading, then it might not have been properly assembled yet.

Yup, it's all OK now. The files were complete, but just locked by the downloading software.