As I can see in your screenshot, the import file does not contain code for base items, also you're using items uniquely identified as Names. Try using "code" and add codes for all the items in the file. Let me know if you have any difficulties in this approach. Thanks!
If I may ask why is there a need to import a list from another list. One there is no filtering out options from source list & you will be replicating the target list, second Anaplan will create an error log if there are any ignores/failures which are highly likely in this scenario.
I would suggest you to create a module based on the source list, create a saved view by filtering out what you don't need and then load the target list from the saved view. Ofcourse by having Code in the saved view and mapping code only, keeping your Name blank or unmapped on the mapping page as it is a numbered list