This version of iForms Designer is intended for use with iForms Server version 2.x on Windows 7 or Windows 8.1. If you are still running iForms 1.x you will need to use iForms Designer [Legacy].
Download the iForms Designer installer and run the installer as a local Administrator. On Windows Vista or above, please right-click on the installer and select Run as Administrator. Follow the prompts during the installation process to complete the install.