There are no syntax errors.
You have two functions: Form_OnLoad and SetDate
Form_OnLoad just disable field new_date when it contains a value and your are opening an existing record.
SetDate runs when you create a new record, add 3 days from today, if the result is a Friday add another 4 days, after check if the result is a Saturday, in this case add another 5 days and set the value to the new_date field.