Are you using manual connect or auto connect as soon as you open LW? As Fabion suggested, it may be an idea to set it for manual connect. Then after opening leave it for 15 mins, then go to menu File>Connect. Don't do anything such as searching or anything else. The priority is for it to connect so let it settle for some time. You cannot rush LW. Let it settle, then try connecting & leave it for a time.

By the way, go to Tools>Options>Advanced>Firewalls & make sure it's set to UPnP & is listening thru port 6346.

Do you have any other computers connected to the net or in a network lan?

Try the manual connect several times. If still doesn't improve, then try deleting the LW preferences again.