Out of curiosity which version of LW are you using?
Has the problem been fixed yet?
Have you tried a connection installer to install a fresh connection file? You can find a connection installer file listed on this page here. If you are using LW version 5, see the link to that page at top of the linked page. There's other tricks to get LW connected besides a fresh connection file, but the things you can try are a little bit different depending on whether it's LW 4 or 5.

One thing that happened to me in recent months was when I disconnected the ethernet cable to give the computer a clean, when I reconnected it accidentally to a different cable slot, it registered the computer as using a different internal ip address & all my port forwardings become non-working. This story did not affect using LW though.