So, this is my problem and sorry for the english, it's not my maternal language.
I downloaded a video file and it was almost completly finished when I closed amule. Then I re-open it to see that I loose all I have downloaded the other day. It indicates in the transfer column that I really transfer this amount, the other day, but in the complete column it shows that I didn't and I should restart my download while it was almost finished. I'm not sure what I wrote is understandable, but I tried!
Thanks for your help!