Some songs in my iTunes library don't seem to be playing, but it's an intermittent problem, and it seems to be limited to songs I've added to my library recently. Last night, these songs were playing fine, but this morning, when I double-click on a new song, it won't play. The files are in my music folder, so the exlamaition mark doesn't appear, they just won't play. My music is all on an external harddrive, and I've been getting the "error 36 - coulds not read or write to disk" a lot lately, but it's just weird that some songs play fine while others don't, and it's a discontinuous problem. Does anyone have any ideas what it could be? TIA!