Weird.

OK--more info needed, but this is a bit more technical.

Click on the Desktop, and use the Go menu to select the Utilities Folder.

In the Utilities Folder, there's something called "Console"

Double-click it, and this will start recording errors.

Then, start LimeWire, and see what Console reports when LimeWire quits.

You can copy and paste the error messages here, or Private Message me with the errors if they look like they might contain personal info. Maybe they'll give a hint what's going wrong.