1. Movie file right? Chances are that at 99% all you'll miss out on is the credits. Why not try to preview it. Use the Explore button on your incomplete folder to open it & remove the file. Then open it up with your video player.

2. Try deleting your LW Preferences folder whilst LW is closed; instructions here: Fixes for Limewire

3. LW will attempt to redownld a file it considers as corrupt up to 6 times before giving up. LW initially downlds the hash tree which has all the info on the file. If at the end of the downlding process this differs from what you have then it tries to recoup that missing bit or byte .. but if the file is corrupt at its source or hashtree has changed then it won't be able to confirm it.