Hi Harley and
. It's been ages since I've used LW and have Never tried a version above 4.18.x, I believe. I'm shooting from the hip here but you might take a look at your Java, as LW utilizes Java to function correctly. It could really be a number of things...i.e. Your security programs, your ISP, a Firewall, and on and on.
You get any errors or pop ups while trying to install??
Hope this helps, but if not, try the forum search function.
Good Luck!!