Exercise in PL / SQL

For these cases, indicating the error message would make it easier for us to tell you that it may fail. Still, I see an error in the way you receive the parameters, you need to indicate if it is input, output or input / output. It would be something like this:

CREATE OR REPLACE PROCEDURE actualizacion (numeroDepartamento IN NUMBER, importe IN NUMBER, porcentaje IN NUMBER)

On the other hand, I would not use the rowcount. I would add a countable variable that increases in each iteration of the loop. Finally, adding the recommendations of B. Pato, the procedure would be something like this (there may be some error, I do not have Oracle installed on this machine and it is impossible to prove):

CREATE OR REPLACE PROCEDURE actualizacion (numeroDepartamento IN NUMBER, importe IN NUMBER, porcentaje IN NUMBER)
IS
    CURSOR c_empleados IS
        SELECT salario FROM emple WHERE dept_no=numeroDepartamento FOR UPDATE;
    v_regEmpleados c_empleados%ROWTYPE;
    v_importe NUMBER(3);
    v_porcentaje NUMBER(4,1);
    v_affectedRow NUMBER DEFAULT 0;
BEGIN
    OPEN c_empleados;
    FETCH c_empleados INTO v_regEmpleados;
    WHILE c_empleados%FOUND LOOP
        v_porcentaje:=(v_regEmpleados.salario/100)*porcentaje;
        v_importe:=v_regEmpleados.salario+importe;

        IF (v_importe > v_porcentaje) THEN
            UPDATE emple SET salario=salario+v_importe
            WHERE CURRENT OF c_empleados;
        ELSE
            UPDATE emple SET salario=salario+v_porcentaje
            WHERE CURRENT OF c_empleados;
        END IF;    

        v_affectedRow := v_affectedRow + 1;

        FETCH c_empleados INTO v_regEmpleados;
    END LOOP;

    CLOSE c_empleados;
END;

The procedures I think were structured with IS not AS:

CREATE OR REPLACE PROCEDURE...
IS
BEGIN
END;

Then in the loop to go around the cursor I think you should go together with% FOUND employees

Add that to use cursors I used more:

LOOP
   FETCH [cursor] INTO [variable];
   EXIT WHEN [cursor]%NOTFOUND;
   ...
END LOOP;

I have not played it since the course, I hope I have given you some light