1. Make sure you have the Extension Enabled:
Type chrome://extensions in the address bar and make sure VidyoWebConnector Plugin is enabled.
Type about:addons in the address bar and make sure VidyoWeb Plugin is enabled and set in 'Always activate' mode.
Select the Tools button, and go to Manage add-ons. Make sure Vidyo Web Plugin is enabled.
2. Make sure you do not have another instance running.