Vista Protection Issue with WMA & MP3 audio files

Hi, can anyone offer an explanation for the following ?
Receiving any mp3 or wma audio file appears to automatically convert
unprotected audio files to protected files. The result being that WMP will
only play them, not offering the option to copy/convert them.
Other audio packages such as 'Jet audio' & 'Olympus (Dictation package)'
will not open them, complaining about CODEX or DRM protection issues.
The above applies to a Vista Home+ system which has been upgraded to Vista
Ultimate to try to overcome the situation - which it does not.
The same audio files work perfectly ok on another Windows XP system and on
another Vista Prof system.
Finally, the systems I refer to are in French belonging to my brother-in-law
who uses it to translate French audio files to English - so, as you can
imagine it's a right pain !

--
Dave