If VoiceThread is not working for you please try the following solutions.
First, make sure you've cleared out your browser cache - here are instructions - http://docs.voicethread.com/troubleshooting/clearing-the-browser-cache/
Next, clear our your cookies - http://docs.voicethread.com/troubleshooting/enabling-cookies/
Then, make sure your flash is updated - http://get.adobe.com/flashplayer/
Also, try another browser - If you are experiencing issues in one web browser and none of the solutions above help, try using VoiceThread in a different web browser. While all modern web browsers should work, Mozilla Firefox and Google Chrome are the best choices.
a. Click the Tools button, and then click Internet options.
b. Click the Security tab.
c. Now click on Trusted sites and then click on the sites button.
d. Enter https://missouri.voicethread.com and click on Add.
e. When you are finished, click on Close.