Flac only BIAB works OK for me. I did a clean install of downloadable version. There must be an issue with Plugin + Flac.
You have .flac + .bt files. The .bt file must be there.
There is a just .flac file option in the shipped disk version that only installs .flac and in that case nothing works. This has been confirmed by PGM.
It takes both .flac and .bt files.
I have only .flac + .wma + .bt and the plugin works with .flac.
There is definitely installation errors with the shipped disc version and most likely issues with the minimal number of files in the Real-track directory for the plug-in.