Not sure about 777.There's probably a terminal line I can use to get info on folder permissions--but I've very limited experience with the Terminal. In Get Info on a folder, I gave the same full read/write perms to the Group and Others categories: same as Owner.

HUGE?--Did note that d/l's from older clients LW 2.7.3, 2.6.5, were more likely to trigger the library error. I tried to trim connections to avoid older Ultrapeers, but that no guarantee of alternate listings.