are you rooted? Nope
what carrier? O2
whats the latest OS update version on the device?4.3
how did you backup the files? Using HTC transfer tool
are you having issues with other files transferred to the device? All other files seem spot on so far
can the music files be played on the computer you are transferring from? Not tried this and not at home with laptop at the mo.
what music program are you using? good question, just the gold headphone as I always have .have you tried other music players? I've tried right clicking to open but no joy, also tried to go on Amazon MP3 where I have purchased some tunes and that won't work either.