Maybe you're talking about replacing the gnutella.net file? There's info about that here: If LW Will Not Connect

If that doesn't help, go through the other fixes. If you're still stuck, post back with your system details.

Just a tip for next time - each forum section has sticky threads posted at the top of the section. The stickies have answers to commonly asked questions & fixes for common problems. The thread that I linked to is a sticky at the top of this Connection Problems section