Depending on the browser you are using, please see the appropriate browser section below:

Firefox

Please check if the Windows Media Player Plugin for Firefox is installed.
Detailed instructions can be found here.
If you need to install the plugin you can find it here.
After installing the plugin you will need to refresh the web cam page.

Opera

Please check if the Windows Media Player Plugin for Opera is installed & enabled.
Detailed instructions can be found here.  You may need to enable the plugin from Opera's Tool -> Advanced -> Plugin page.
After installing the plugin you will need to refresh the web cam page.