Adobe recently published a new version of Flash. Make sure your flash player is current (I've found not having the current version breaks things in FormsCentral sometimes). Also, if you are using IE8 or above, try clicking the compatibility mode button in the address bar (it will look like a torn piece of paper). It could be Excel as well, make sure you have all the most recent security updates for Office. If you haven't rebooted your computer in a while, you may want to reboot as well, I've known things to get gummed up sometimes if you computer hasn't been restarted in some time.
Hope this helps!