Your problem is that the field is probably datetime data type and the code for that would be;

* Convert the Datetime value to a date value
ldDate = DATE(YEAR(MyTable.MyField),MONTH(MyTable.MyField),DAY(MyTable.MyField))

lnDayNumber = ldDate - Date( YEAR(ltDate), 1, 1) + 1

>error"Funcation arguments value or type or count is invalid"
>
>But when i write ldDate = date() no problem.
>I am using vfp9 sp1.
>thanks