Yes you are under the heirarchy, but the option vlan-tagging was not configured. So this opotion is configured at the physical interface heirarchy as shown
You must set the vlan-tagging parameter under the [edit interfaces ge-0/0/1]
any configuration under the unit numbers would represent logical properties
Without eabling vlan-tagging, the only logical unit number you can configure is unit 0. Enabling vlan-tagging allows you to configure unit 0-4095 if the switch allows it.
set interfaces ge-0/0/1 vlan-tagging
BTW you will also get this error if you try to configure family ethernet-switching under any unit number other than 0