This is not really obvious: Windows Media Player refuses to open a Windows Media (ASF) file with an undescriptive error message: “Windows Media Player encountered a problem while playing the file”.
The problem, however, is that the file is actually good, more or less. The file plays well in DirectShow and Media Foundation APIs. There is a unusual thing, of course, that the file contains two audio tracks. The tracks are mutually exclusive as they should be (exclusion of language type – MFASFMutexType_Language).
It appears that Windows Media Player does a strict checking of language strings, and expects them to be RFC 1766 compatible. They are free style tags in this file:
Not a valid language string? OK, no playback then.