Why won't ares locate my song?

I have used ares galaxy to put about 100 songs onto my itunes and it always works perfectly. But today I downloaded a song and when I t completed I right clicked it and went to locate file ( as usual) It then continued to open up all my files. The only problem is that the new song I downloaded wasn't there so I couldn;t transfer it to my itunes. I dont know what to do! Please help