There might be a possible corruption of the LW preference folder. You can try and delete it to see whether that will bring any changes.
Read here on how to delete this folder (Point #2 & 3 in Fixes for Limewire)
http://www.gnutellaforums.com/showth...threadid=36420
Afterwards reboot your computer.
Another possibility is that you ISP has started to shape your bandweidth usage.
