Heyy please help me i have been trying to download movies from btjunkie site..it worked always last time few days ago then suddenly it tells me error downloading torrent..why?

Maybe a communication error between LW and the torrent site. Perhaps if you restart LW it will fix up again, else pause it & then resume to the download.

Other issue I can think of is there is nobody presently seeding that torrent, else the torrent's url is incorrect.

For torrent downloading it is better to use Vuze or uTorrent (both are free). LW doesn't track share ratios, so you are probably not getting the faster dl speeds available. Also, LW is banned from some torrent sites.