you have not defined a root partition (/), which is required for installation or Red Hat Enterprise Linux to continue

Hello - I am trying to set up RedHat 7.1 Server to house a Oracle 12c server. So I am creating this on VSphere 6.0. the problem is that I am encountering is the following error message "you have not defined a root partition (/), which is required for installation or Red Hat Enterprise Linux to continue. You have not created a bootable partition". This is happening when I try to create the mount points during the installation of the Red Hat server. The issue is thought that I have created the / partition and it is visible. Can anyone offer any enlightenment. Thank you