To fix this issue, all you need to do is change the flash setting in Google Chrome. Here are the steps:
1. Go to your settings in Google Chrome. Do this by clicking on the 3 dots in a vertical line at the top right of the screen and clicking 'Settings' towards the bottom of the menu.
2. Go the bottom of the page and click on 'Show advanced settings...'
3. Under Privacy, click 'Content settings'
4. Once that menu pops up, scroll down to 'Flash' and select 'Allow sites to run Flash'.
5. Finally, go back to the tab where the highlighting guide is and refresh the page.