I am running OS 9.2 on a G4 and no matter what version of Limewire I run it invariably crashes when I launch it. I've increased the memory and that hasn't helped. The icon turns into a thing that looks like a little square of data. Please help!

There might be an extension conflict. Open the Extensions Manager in the Control Panels and select "Mac OS x.y All" where x.y is your OS version. Restart and see if the problem went away.