Try again. Open LW and go to Tools>Options>Searching>Basic, Tick "Show License Warning" > apply > ok. Then try d/loading something. This time when the license message popsup, check always use this answer and select yes.
See:
License Warning Option.
If that doesn't work, try deleting your LW Preference folder. Instructions in this thread points 2 & 3(check both locations):
Fixes for Limewire. This will reset all your option settings, so make a note of them first.