A message appears on the page, "Javascript is either disabled or not supported by this browser" and a symbol appears on the page where it hasn't loaded properly. This has happened after I downloaded a Firefox update. Some pages will not load or function and display a similar error message. I enabled both Java & Javascript in the Options section on the Tools menu.
Check what's selected under the "Advanced" button next to "Enable Javascript". Sounds like you might have disabled something that that web site is trying to use.
If that doesn't work, try a new profile. If that doesn't work, you might need to remove Firefox via Add/Remove Programs and reinstall the full 1.5.0.5.