When attempting to set a pledge for only one installment the following prompt can appear:
The following error(s) must be corrected before continuing:
Number of installments must be a whole number greater than one and less than or equal to two hundred.
A pledge installment must be between 2 and 200 installments.
Note: If the user wants to make a pledge with a one time payment, then enable the bill me later option on the donation form. The user will submit a one time gift and choose the bill me later option so that they can pay at a later time.