Re: Data Import Error - “Key for this row maps to more than one list member”
The hierarchies should not have same list members rolling into multiple parents.
If there is a requirement you should make a Numbered list and then provide appropriate display name. Numbered list uses code value to lookup a list item hence it will never be concerned with what display name you provide.
Anaplan also provides an option while importing (handle duplicates), where duplicates are handled by appending "`1". But then that means same name is never possible in the hierarchy.
Please note you should never have same list items in the hierarchy rolling to two different parents. Hypothetically if you ask system to look up say "List Item 1" and the same item is available under Parent A and Parent J which one do you think the system will pick?
Hope this helps. Design the hierarchy using a numbered list.