I am also sorry to tell you that Limewire LCC has no control whatsoever of what is being shared. They just offer the program, not the experience to filter out these malicious files. All files that you get from the Gnutella Network are being shared by other users. And yes some of those are pests and just out to hurt the network and the people using it. Many of them can probably be traced back to the music- or movieindustry.

I can only advise you to search the forums for threads regarding how to stay away from these bad files

Also add words to the keyword filter
It can be found in "tools<options<filters<keywords"
you can also add extensions ((for example: .mov or .asx) remember the period when adding extensions) or mov will filter movie etc.

You can start here:

Viruses on the network

search button can be found in the upper right corner