If EzeScan is installed with User Account Control (UAC) set to ON, some important EzeScan dll's are not properly registered.
When installing EzeScan on Windows Vista it is required that User Account Control be set to OFF for the user installing it. It is also required that the user has Local Administrator permissions or ideally install from the Local Administrator Account.
To disable User Account Control for a user account….
Select Start Menu → Control Panel
Select "User Accounts"
Select "Turn User Account Control on or off"
Uncheck the box "Use User Account Control (UAC) to help protect your computer"
Restart the PC for the changes to take effect and then try a new installation of EzeScan