I don't get a message that says "could not move to library" but have the same problem. I just installed Limewire (for MacOS X), got about 5 songs, and now a download will complete but not be stored in my library. The file is not on the hard drive, there are no weird characters, and quitting/restarting Limewire doesn't help. There's no point to downloading files I can't do anything with, so somebody please tell me how to fix this!