Error from Fast Formula a local variable was used before being initialized

Summary:

I created fast Formula, but when i run showing error as below

 line 57, a local variable was used before being initialized.

and this lin 57 as below

L_Length_of_service = Round((DAYS_BETWEEN(LEAST(L_EFFECTIVE_DATE,PER_ASG_REL_ACTUAL_TERMINATION_DATE),GREATEST(PER_PERSON_ENTERPRISE_HIRE_DATE,PER_PER_LATEST_REHIRE_DATE))+1)/365,2)

and this code for Fast Formula as below:-

/*****************************************************************************

FORMULA NAME: Education Fees Request

FORMULA TYPE: Payroll

Author 		    : Ramy Omar

Creation Date	: July-2024

*******************************************************************************/
/* Database Item Defaults */
DEFAULT FOR amount                         is 0

DEFAULT FOR mesg                           is ' '

DEFAULT FOR ENTRY_LEVEL       IS 'AP'

DEFAULT FOR PAYROLL_PERIOD_TYPE IS ' '