This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".

This error suggests that something has not yet been prepped in IIS. Type "turn windows features on or off" at the search at the charm bar in Windows Server 2012 R2 Datacenter to get the "Add Roles and Features Wizard" anew, then... well, you know...