This is an issue that seems to occur because of global privacy settings for Flash Player. You can fix this issue with the following steps:
Step 1: Right-click (or control-click on the mac) on the screen in Adobe Connect and a pop-up menu will appear
Step 2: Click on "Global Settings..."
Step 3: The Flash Player Settings Manager should pop up, then select the tab for "Camera and Mic"
Step 4: Click on "Camera and Microphone Settings by Site"
Step 5: Click "add" and write in "columbia.adobeconnect.com" under "Website Domain"
Step 6: Choose "Ask me for permission" and then click "add"
This should resolve the issue. If this does not work then you can try adjusting your security settings at the site below:
Flash Website Privacy Settings Panel: http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager06.html