So you've been able to install LW in the past? Which was the last version that installed properly? What's changed since then - new hardware, new/updated software etc?
Have you tried installing older versions of LW, to see whether the problem's version related? Try the older version in post #4.
Have you been able to install other p2p apps that aren't Java based (LW, Phex & FW all are)?
Try the version of BearShare mentioned here & see whether that installs:
http://www.gnutellaforums.com/open-d...sabotaged.html
Did you try reverting back to an older Java version (in the 'fixes for LW' link, there's a link to an older Java)? When you switch Java versions, are you making sure to run only the one version of Java at a time?