off topic: What has been seen... :P
on topic: I have further developments.
Before going to dinner I connected my kindle to a power source and left it with wifi on in sleep mode.
Came back and the sorting finally works.
Also the clock changed the time, it was set (by me) to 21:00 and when i came back it now indicates 15:00 showing that it finally has synced with the amazon server i guess.
Now the question is what made it finally sync? The fact that it was connected to a power source? Or does it just need some time to finally talk to the amazon server?
Also, and most importantly, how can I prevent this from happening again?
ixtab tahnk you very much for the input. I don't know how to work with sqlite but if this happens again I think I can learn just enough to read the data regarding the dates, thanks for the idea!