Might be corrupt files or something similar.
Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see).
Try Get More Results via right-clicking the search tab. If using LW 4, you can cancel the download & re-select from search results, this often works. Do not do this with LW 5 as it deletes the incomplete file.
For FrostWire, depends ... if you are using the same download folder, then it will share the same download preferences.
This was true for LW 4, however probably different for LW 5.