I assume your first question is rhetorical.
You have given no information about your computer, OS or anything else so I have thrown a coin in the air and it came down suggesting this might be the answer.
http://www.gnutellaforums.com/showth...176#post154176
If this doesn't help we really need a shred of something to go on. The forum rules at the top of the forum suggest how you can put a question, and there are stickies there too which might well help. Have a good look through them.
The following is from the Limewire support page, which covers the firewall question and the link to the user guide is also there.
http://www.limewire.com/english/content/firewalls.shtml have a look there too.