I'm guessing these are gnutella network files then, not a torrent file you downloaded initially off a web site & opened with LW.

To re-search the file(s) simply type in the search box as you did previously. After 5-10 minutes, right-click the search tab & choose Find More Results. Sample image below:


Hopefully this will result in more hosts with same file, and some will be able to be downloaded from. If this does not work, then choose another option from your search results instead.