The T5 is fairly easy going concerning the mp3 bit rate of files (64-320 kbps), but it will only play those sampled at 44.1 or 48.0 kHz.
However if you are trying to load a file with different specifications, you should only get an error message when you actually try to load it, and the files should still be listed for selection.
If however your files are not even being listed in the selection screen, then either you are not in the 'Audio' selection screen, or there is a problem with the file name or extensions.
The 'Audio' file selection screen is opened by first pressing the AUDIO RECORDER/PLAYER [MODE] button to call up the AUDIO RECORDER/PLAYER display. Then press FILE (button A) from this screen to open the selection screen.
The extension must be '.mp3' (or'.MP3'), and the total length of the name (including the extension) must be no more than 50 characters.
You should check the files on your computer using Windows Explorer or the like, set to show the full name and extension of the files. If they are too long, you can simply shorten them and they should then be listed by the Tyros.
If the length is not the problem, could there be some unusual character in the name that Tyros does not like?
Regards
Ian