Problems using LW on Mac 10.5.4

I just bought my 1st Mac and I installed LW. It worked the 1st day, but now when I run it, it opens, I choose Later and it shuts down and says "The application LimeWire quit unexpectedly. Mac OS X and other applications are not affected."

1. OS version? Mac OS X 10.5.4 I do have an Administrator user account.
2. What firewalls you have? Whatever came with the system.
3. How much ram?
4. Hard Disk space available? 201.79 GB
5. Connection type? Cable Modem
6. Modem & router brand name & model numbers? Arris TM502G
7. Where are you trying to connect from? House
8. What version of LimeWire (LW) & Java do you have? LW= 4.18.3 Java= 1.5.0 _13
9. Who is your ISP (Internet Service Provider)? Comcast
10. Do this simple test for us. Using your browser go here: It say 'Your test worked!'.
11. Are you sharing the connection with other computers or p2p sharing programs? No
12. Is this a your 1st try at LW or is this a new problem with an experienced user? New problem, experienced user, new system
13. Do you see a brick wall in front of the blue world icon at the bottom of LW's interface? yes
14. For those using a modem/router, how is your modem/router set up...are you port forwarding or is UPnP enabled? I have no idea what this means.
15. What security programs are you using (antivirus etc)? As far as I know, none. Unless the system starts one on its own.
16. What country are you living in? USA, Michigan Detroit suburb