Prom with Importing File into Multi-track

This problem just started.  I was attempting to insert an mp3 into multi-track and it will not show up.  For soem reason it will show up in Wave view but will not into multi track.  None of the files from this folder will.  I tried another folder and they transfer fine. I even ried trashing the folder and the files and starting a new folder and re downloading the files into a new folder.  What is funny is all the other files in past folders download fime.  I checked files in a folder before and in a folder after and even before and they insert fine can somebody tell me whats going on