How to calculate prorations for earnings n deductions

Question

when i am trying to include the proration code in house allowance fast formula it give me error. This same code works fine with Basic Salary FF only but with house allowance and other allowances n deducitons its giving me the following error:-
APP-FF-33065: Line 68: Only database items or input variables can be defaulted.
Cause: You have specified an item to be defaulted which is not a database item or an input variable.
Action: Use a database item or input variable in the default statement. If you want to change the value of a local variable, simply assign a value to it. You can change global variable values using the Manage Globals form.
Now, Line 68 refers to the following line that i have given in my fast formula:
IF (prorate_start was not defaulted) then
l_days = days_between(prorate_end , prorate_start)+1
day_in_Month=days_between(PAY_PROC_PERIOD_END_DATE,PAY_PROC_PERIOD_START_DATE)+1
House_allowance = (House_allowance * l_days) / day_in_Month
     House_allowance=(House_allowance)
     House_allowance2=(House_allowance)
     House_allowance_tzs=(House_allowance*EXCHANGE_RATE1)
please note the folloing has been mentioned as default in this FF:
default for prorate_end is '01-JAN-1900' (date)
default for prorate_start is '01-JAN-1900' (date)
default for PAY_PROC_PERIOD_END_DATE IS '01-JAN-1950' (date)
default for PAY_PROC_PERIOD_START_DATE IS '01-JAN-1950' (date)
I am trying to compute the employee earnings n deductions based on the number of days the employee has worked.
Please assist/help me!

Answer 1

i think the prorate_start is a variable, other wise check the spelling is correct as the input values or database items.
if it is a variable, then use isnull(prorate_start) = 'Y' instead of Defaulted
zamora