If this error is received it would indicate that an additional payment is present on a staff contract that is no longer valid. To check this:
- go to Admin > Personnel > Staff
- find the member of staff the error relates to
- click onto the black cog next to the contract
- view the additional payments
If the payment type is incorrect for the valid payment types this year you can delete the payment:
- click onto the red cross
- re-add with the correct payment type in the additional payment area at the bottom of the contract
- save the changes