my mobile sonyericsson w200i has the following problem
1. during mp3 playback hearing intermittent 'tick' sound
2. play back failed in the middle of the song with error message as 'failed' or 'playback failed'
I was facing the exact same problem with my W200i. I formatted my memory card using the "Quick Format " option and then re-uploaded my songs. That solved my problem. There is no disturbance in between songs now, also the "Playback Failed" error has also not occurred again.