You need to create the cotnroller, set it to 100%, set the pose you want it to put into effect, and only then do you do ERC Freeze on the controller. ERC Freeze looks at non-zero properties and links their local changes (not anything caused by an existing link) to the property you issued the ERC Freeze comand for, so that when it has its currently set value they will assume their current local values. It sounds as if you are doing it backwards - trying to create the link, then add the property.