Carla:
It really sounds like you're trying to save changes to an Enterprise Project
View and not an Enterprise Project Template. In order to make changes like
this, you need to checkout the Enterprise Global Template which contains the
enterprise views. So it sounds like you want to add the published column to
a specific view. In that case, Open Project connected to the server, apply
the view that you want to modify, Check out the Enterprise Global, add the
column to the view, save and close the Enterprise Global. (Note: do not
apply other views while you're editing this one and have the Enterprise
Global open otherwise you risk polluting the Enterprise Global file. This
change will apply to all users of the view.
If you want an Enterprise Project Template to contain a local view with this
column exposed, you can copy the view into the Enterprise Project Template
and save it. This view will only be available to users who start their
projects using the Enterprise Project Template.