so it turns out that I can't delete those files from within Limewire either! While in the library tab, if I try to delete one of those files from the listing, I get a limewire error box: "Unable to delete the file '[name]'. It may be in use by another application."

Nothing else is running, and I have no uploads, so as far as I know, it isn't being transferred anywhere. double-checking shows that the same files I can't rename in windows can't be deleted by limewire, but everything else can-- and it's still about 50% of the files... and exiting limewire again solves the problem.

I suspect that Limewire's tying up these files somehow and doesn't know it. Is this just a bug, or solar flares, or what?