This error message suggests that a Use By Date on the manual carryover use by field is set to greater than one year.
SelectHR only allows you to take carryover up until the last day of the following holiday year, so you will need to correct this by following these steps.
Under Absence, click Absence, then Holiday History.
Open the employee record.
Open the Holiday Year record.
Tick Don't Recalculate.
Change the Use By to be a date that is within the next Holiday Year.
Click Save.
Untick Don't recalculate, then click Save.
This should allow you to successfully save changes to the holiday year record.