I went to the site and enabled most of the scripts. I didn't have a problem with the site using Firefox 3.0.10.
You might try the noscript plugin. Also kill the npviewer.bin process if is hung. You could also start firefox with the profile manager, or in the safe mode:
Code:
Mozilla options
-height <value> Set height of startup window to <value>.
-h or -help Print this message.
-width <value> Set width of startup window to <value>.
-v or -version Print Firefox version.
-P <profile> Start with <profile>.
-ProfileManager Start with ProfileManager.
-no-remote Open new instance, not a new window in running instance.
-UILocale <locale> Start with <locale> resources as UI Locale.
-safe-mode Disables extensions and themes for this session.
-jsconsole Open the Error console.
If you create a new profile and run firefox using the new profile, that might give some clues whether the problem might be with firefox or a script in your original profiles environment.
Good Luck!