oh .. yes unfortunately LW 5 is not compatible with OSX 10.5. You will need to instead, install LW 4. I would however recommend LW 4.16 rather than 4.18. See
http://www.gnutellaforums.com/mac-os...link-here.html & instructions about removing the 'newer' LW Receipt file before installing (otherwise OSX will not let you install LW 4.)