Error : Invalid isperson reference key (customer name)' When Importing Customer Records via CSV Import Assistant

1. Navigate to Setup > Import/Export > Import CSV Records.
2. Set the following fields:
        Import type = Relationships
        Record type = Customers.
3. Select your CSV file.
4. Click Next
5. Set Data Handling to Add
6. Click Next
7. Map all mandatory fields.
8. Map Individual (Req) or click on the pencil Icon and select Yes or No
9. Click Next
10. Click Run

isperson is the fieldID of the Company Type field. Individual or a Company should be specified on the CSV Import.