I had this problem too (installed wrong version for update purposes, then unable to reinstall, even after dragging the downloads and Limewire from Applications to trash, and emptying the receipts folder).

But then I used finder to search 'limewire' and some other folders came up in library (preferences and one other thing - theme and props, too) and after deleting them, my download and install worked. I don't know if this helps anyone, but in case anyone comes across it. I know this thread REALLY helped me to troubleshoot, so.

Thanks!