I can't play Optimfrog files on Foobar2000 because the plug-in gets this message:
Failed to load DLL: foo_input_ofr.dll
Reason: Not a valid Win32 application.
I'm on Windows 10. I've tried both files inside foo_input_ofr_130.zip and foo_input_ofr_131_test.zip, in the codec website.
An update: I had combined "foo_input_ofr.dll" (from 2011, the most recent) with "OptimFROG.dll" from the latest version (2015). On my system, they don't work together. So I extracted both files from the 2011 version, and it finally worked. I don't know if this is expected.
Make sure that you use 32-bit OptimFROG.dll.