Have you tried refreshing the browser cache using the instructions on this page? We see most users have been able to get through that level if they are using the updated version.
In all browsers there are methods to "force-reload" a page without using your cache.
Windows and Linux browsers:
CTRL + F5
Apple Safari - either of these two methods:
SHIFT + Reload toolbar button
COMMAND+ OPTION + R
Chrome and Firefox for Mac:
COMMAND + SHIFT + R
After this, if you still get the same error, please send a note to email@example.com and can mark this a complete so that your child can continue with the course.