Mozilla Firefox 5.0 Encryption Problem

I'm having this kind of problem, that if I open my working website there is a warning that the website uses a code that is enabled. So I went to options > advanced > encryption and I saw there that both ssl and tl are enabled. I can even open the website in my latest IE version and it works fine, and can open the site in an older version of Mozilla. What makes it so difference?
And my second issue is whenever I opened MF, I got a message "A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete". It is very irritating when I open Mozilla Firefox.
Somebody would help me on this please?
