If songs are constantly queued, try the advice here: All downloads Queded

Once you were able to download, it sounds like you found some junk. Some junk files will give you the 'already downloaded' error, even though you haven't downloaded the file before.

Try this: Use the All Types search > search for artist name or album name, rather than song title > choose a file with 10 sources or less, or even a file with a single modem source.

In LW click on your Connections tab. Now you'll see 3 or 5 hosts that you're connected to (number depends on whether you use basic or Pro). Right click on a host > remove. Do this for the hosts that you're connected to & new hosts will replace the ones that you've removed. Start a new search & see whether you get different sorts of results.

There are lots of spam/junk files shared by companies who want to sabotage p2p. There are also lots of infected files being shared!! Make sure that you have a good antivirus program. Keep it updated & use it to scan every file that you download - before you open it

Check out these threads for more info about what to avoid, some general virus info & info about fake files:
Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)

* WARNING: Viruses on network you should be aware of ! *

Fake files showing up in search results

How to find music