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.
Log into access your profile, ask and answer questions, share ideas and more. Haven't signed up yet? Register