Sounds like it. Stay away from the files with hundreds of sources, fakes typically show huge numbers of sources. Instead, try a file with 10 sources or less, or even those files with a modem source.
Try searching using the All Types search, look for artist or album name rather than song title...that might bring up some different results

There's more info in these threads.
Fake files showing up in search results
How to find music

That seemed to work. I just looked for more sources several times and picked ones that look a little different from the one with hundreds of files. Thanks.

Thank you guys, after a long search I found this topic with very useful links...

I had the same problem, one particular song that I couldn't download. I thought something was wrong with Limewire so I re-installed two times, did countless checks on my connection until I thought... Let's try to download another song ! That worked perfectly so I was sure Limewire worked properly. I then started looking in the forums, but there are so many subjects !!! But after one hour I ended up here, and now, by looking up via the album name instead of the songs name I succeeded.
I also fine-tuned my Limewire with some of the tips I found under these topics.

Thank you all !!!

Michel