The latest Converter is 5.5 and I've recommend you to use it. (it's better to install in client/server mode)
If you want to convert WS images to ESX then you need to choose 'Vmware Workstation or other VMware virtual machine' as source, poining SMB share, and choose 'Vmware Infrastructure' and put your ESX name/ip and credentials. (you'll need to connect Converter UI to your Converter Server through name/ip instead connecting to 'local server' too).
HTH