This has nothing to do with copy protection, so this will probably get moved or deleted soon.
Using Kazaa Lite (K++) is unauthorized software that connects to the Kazaa network. That's why it may not work for people anymore. Kazaa Lite Resurrection is a new incarnation that should be able to connect and work on Kazaa's Network.
What is legal and what is illegal... MP3's in general are not illegal. It comes down to if it is copyrighted work or not. Any software that you would have to pay for or if it comes with a serial or crack, then it is most definately illegal to download. Any Movies, actually most porn videos too, are illegal to download.
MPAA and RIAA are the biggest forces behind cracking down on downloading, so if you avoid MP3's and movies, then you probably won't get sued anytime soon.