It is possible that you are downloading fake files. There are a lot of these around... I wonder too if you are perhaps doing an audio search and filling in an artist AND a title. Doing this tends to produce many irellevant results. So just fill in one prtion of the search pannel and download files with less than 20 sources.
If you are just starting out , try a "what's new" search. I'm not sure the results are that new , but they do usually give mainly decent downloads. Try a few of them and see how they go ..
Let us know if you need more help
