You might have an issue with your installed VB Script. Try creating a new user profile with local admin rights and installing as the new user. If that doesn't work, make sure you have the latest version of the Windows Installer.
Error 1720 doesn't happen very often and it indicates a problem with your Windows and not the Autodesk software.
Start with some of our most frequented solutions or visit the Installation and Licensing Forum to get help installing your software.