ECS V5.1 installation in Windows 7 64 bit edition
to install ECS in an Windows 7 64 bit environment you need to install "Windows XP Mode" first :
http://www.microsoft.com/windows/virtual-pc/default.aspx
This installs a virtual machine with a ready to use Windows XP (520Mb download).
In this XP you can install ECS without any problems.
If it is installed, you can start ECS directly out of Windows 7 without the need of starting the virtual machine.
You can even use a serial to USB converter.