LW settings are saved in the Home/Library/Preferences/Limewire folder. Delete that, and all your settings are gone. Lord of the Rings has instructions for "uninstall" in the stickies. Your situation, however, probably just needs to delete the LW "Incomplete" folder. Clear all downloads in LW, view the Library, go to the Incomplete folder, and delete the file that is a problem.

The info you found about a Windows user looks like they had a virus or other non-OS X malware problem, since their machine "remembered" settings after an erase and install of the system.