To find out which song has the screetching noise before downloading...look at the quality of the song. if it isn't standard quality (for example 56kbps, 128 kbps, 192 kbps, 256 kbps are the common quality mp3 files) then do not download.
for example, if you download (Fountains of Wayne - Stacy's Mom) and the quality is 178 kbps, then do not download. instead download another one that has a quality that is 128 kbps.
sorry, i can't make it any more clear, if any problems, reply back to me. THANKS!