Error message not helpful when trying to designate a non-unique field as the primary key

When importing a csv file in the Import Business Objects wizard, the import might fail when you try to designate a non-unique field as the primary key field in the wizard. You might see an error similar to this:

<BO Name>: Error renaming field "<Field Name>" to "X#" on  entity "<BO
    Name>" <BO Name>: <number of rows> exist

If you see this error, to import the business object you need to select a different field for the key. To be valid, the field must contain unique values.