These are the things to be considered to bypass the error:
1. Entity Record (Customer, Vendor, Employee, Other Name) should be currently active.
2. Check the entity record (Customer, Vendor, Employee, Other Name) and ensure that the value in the CSV File has the same format based on how it is listed in NetSuite.
3. Check the Entity Record and makes sure that is has the same Currency as the Journal Transaction Currency. User can assign the Currency as Secondary Currency in the entity record if its Primary Currency is different than the Transaction Currency.