There is also 
Hostiles List which can simply be added to the LW preferences folder. 

 However I'm not sure if it is compatible with 4.8.1, edit: 
http://www.gnutellaforums.com/263954-post9.html 
You could at least use those ip's to block manually. 
BTW LW 4.8.1 was my favorite version for a long time, IMHO better than versions up to at least 4.12 or perhaps 4.14.