Because I never had such problems or use Firefox or any of these additions, I don't have any idea what to do about your specific problem. But if the scoreboard with the automatic updates is not working for you, you still have the chance to watch the "standard scoreboard".
Go to "matches in progress" and if the scores don't update live for you, then watch out for the link near the bottom of the screan that says: "Problems viewing scores? Please visit our standard scores page here."
This is a normal html page which should load for sure, the disadvantage is that you have to update manually.
Carlos --- C'MON Lleyton!!! --- Kiwi!!! --- Jürgen --- Juan
Best of luck to all Germans : Nicolas Kiefer | Rainer Schüttler | Lars | Florian | Tommy