Try to get as many sources of the file as possible. Repeat the search from time to time. Also if you're dwnlding many files at once, the source may be swapping preference over to another uplder from time to time. So be patient.
Here's some hints: A well set-up LW can start to automatically continue its dwnlding after it's settled down perhaps 2 out of 3 times you open LW. Optimising LW & Maximising Uplds & Dwnlds A (1st post only) & also Part B which is even better & last & least are search & dwnld hints. The latter one I've been thinking about re-writing for some time. That's just for playing it safe. eg- I show all speeds & qualities.