I have downloaded the latest version of LM on my XP O/S desktop from 2003. A prior version 4.9 worked a few years ago. However, when launching the 4.9 application. I had the firewall issue. I downloaded the latest version of LM and the same problem. I have Norton 360 as my security software and it appears it added LM correctly. I tried adding the port number as well. I disabled N360 and still didn't work. I was connected by internet via LAN and even disabled and connected via wireless. All still resulted in firewall issue. I then downloaded LM on my laptop and it works fine. My laptop only has norton internet security. I am assuming my desktop and laptop internet sercurity programs are different. Lastly, windows security is not being used. Any suggestions??