2 different things here... I'm not sure where you got Limewire from, but I'm suspecting it was not Limewire.com. Paying for the pro version does not make the downloading of Copyright material any more legal, although many people use Limewire perfectly legally downloading material that is not copyright.
This thread may be of interest .. (some of it at least

)
http://www.gnutellaforums.com/showth...threadid=28751
As for the pop up .. It does mean what it says. There is more about it here
http://www.gnutellaforums.com/showth...176#post154176
Let us know if you need more help. And Limewire ... Open discussion would have been a better place to pust .. (Next time) .. for now stay her for this subject