Please check the HELP Loan Amount (E558) and the Student Status Code (E490). Where the Student Status Code (E490) indicates that the student is not accessing a loan, the HELP Loan Amount (E558) must be 0.0.
Error Logic
If the Student Status Code (E490) is '111', '112', '202', '203', '204', '250', '260', '261', '262', '270', '271', '301', '302', '303', '304', '305', '310', '311', '331' or '501' to '510', then the HELP Loan Amount (E558) must be 0.0.
Loan Fee Amount is incorrect (It could be that you have the Unit Enrolment set as FEE-HELP, but the E490 field is set to UPFRONT). Resubmitting the Unit Enrolment with the correct (consistent) values should fix this error.