You must have Internet Explorer open.
Click on the settings icon on the top right hand of the window and select Internet Options...
Select the Security Tab to see the following screen, and the click on the Trusted sites icon and finally the Sites button
Type http://ams.det.nsw.edu.au into the top field. The Add button will be enabled.
Uncheck the Require Server Verification checkbox if it is checked and then click on the Add button
Click OK/Close to return to the previous window and ok again to close the Internet Options window.