If you have version 0.4.9 - update to 0.4.91 you miss the bug fix.
If not try this:
1. Re-enter the room.
2. If it didn't help, then star over, and this time follow the story in the dialogue (Do what you're told).
''Often the problem with the bed is directly related to Player's action, and for some reason people try to go to bed on a night when they need to grab an mp3 player and go to the park instead.''
Also you may not have taken the MP3 from the bed XD