Oracle Error Message
PLS-00521: ORDER methods must be declared with 1 (one) parameter in addition to (optional) SELF.
Reason for the Error
An order member function was declared without the user-specified parameter. Order member functions have two parameters, one is the default SELF parameter which is added by the compiler. the second parameter is added by the user and must declare an order method which must be the same type as the containing object type.
Solution
Check and correct the way the parameter is specified.