Cannot play .flac or .wav files

[minsky]

Is there any error message?

No, there are no error messages displayed. I have also tried connecting the USB lead before and after the tablet was switched on, but that didn't make any difference.

For your information, the .flac and .wav files were created by ripping a CD using Exact Audio Copy, and the .dsf files were created by converting the same ripped .wav files using Tascam's Hi-Res Editor.