limewire and kazaa

I was told that by getting limewire, I'd be able to access kazaa and begin downloading music files to my I-Mac -- something I cannot currently do. So I bought and installed limewire, downloaded kazaa and limewire refused to activate it because of security reasons. I was warned before download that the package might contain a virus. HOW CAN I GET AROUND THIS AND HOW DOES ONE CONTACT THE FOLKS AT LIMEWIRE TO GET THEM TO EXPLAIN THIS?