lol The bitrate is the br the song was encoded at. It has nothing to do with dwnld speed. The higher the no. the higher the quality of encoding. To my knowledge an mp3 can be encoded from about 30 up to 320.
Problems dwnlding a particular file, do another search to see if you can find more sources for it. You can also cancel it from the dwnld list & re-select from the search results. This can work. Occasionally searching for more sources as well.