1. Who is your internet service provider (ISP)?
2. Try an experiment by downlding a magnet link from here & tell us what happens: http://www.magnetmix.com/video.shtml
3. See License requirement (click on link)
4. Go to LW's menu bar, Tools>Options>Downlds & make sure the no. is one or more. Then go to Options>Uploads>Slots & make sure there's at least one slot open.
5. Consider deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included.) See if that makes any difference.