Problem with my % dropping on my download
 

I was downloading a .avi file it's over 600mb and i've been downloading it on and off for 3 days now. it was at 66% then next time i open limewire it went to 17% when i started downloading it. I was wondering should i be worried about this or is it gonna go back to the percent before? Because i can go to the incomplete folder and open the file and skip threw parts of it when i play it in media player classic. But i can tell it's not fully complete but i know it's more then 17% complete. So is it just going back to download in the rest of the piece's of the file or something? could somebody pls help thx in advance