Chances are you need to update your version of Java.
My knowledge is so primitive, that I don't even know what this sentence means!
Java is a scripting language that your browser interprets to run certain parts of the forum (and other Web sites). If it's not up to date, your browser may not know how interpret Java scripts, and that can likely cause your browser to freeze or even crash.
I finally got a chance to check the access_logs and I see that you're using IE6. Do you have automatic updates set for Windows, or do you check for updates on your own using Windows Update? If it's the former, your version of Java *should* be up to date, but when it comes to IE, I've learned to never count on anything.
And another complication is that you may be using Microsoft's own version of Java. They've been court ordered not to use or distribute it any longer - but I strongly suspect they've never removed it from the Windows users who've already had it installed - especially the Win98 users, of which I also see you are.
If you go into Windows Control Panel, do you see an icon that looks like a steaming cup of coffee that's labeled "Java"? If so, click it, and then check which version of Java you currently have installed on your computer. You really shouldn't be running anything less than Java 2 version 1.5.0 - preferably even build 11.