no i think its a battery problem as mentioned by me before. the same things happened to me and a change of battery worked.
try it and let us know of the result
you could also open up the battery cover at the back of the player. see if the battery is moving a lot and if you think it is, insert small pieces of paper wherever possible (bottom, left, right of the battery) so that the battery fits correctly and makes good contact with the gold pins on top