These threads have some good tips in them...
What you should know about WMA Files
WARNING: Viruses on network you should be aware of!
How to add words to the filter
Keywords worth filtering
Also....
Try installing PeerGuardian, it will help keep the fake hosts out...Remember to enable PG just before you start limewire up...
Phoenix Labs ยป PeerGuardian 2
If you're using Vista, there's this PG2 Beta available for Vista users.
PeerGuadian 2 for Windows Vista beta released - Phoenix Labs
PeerGuardian 2:Manual - Phoenix Labs Wiki
Another thing if you are using limewire 4.13 and later you can apply this hostile list...
The TechNutopia Fullsize Hostiles List for BearShare and LimeWire