Hi, Check if your field (gpreis) is declared as Class String. By the error that it's giving to you I'm suspect that is declared as a number (Integer or Double). Anyway I believe that it's better if declared as a number, since you want to sum it. To do the sum declare other variable with "Calculation Type" set to "Sum" and "Variable Expresion" to $F{gpreis}. You must put the reset type according to your needs, "page" in your case if I didn't misunderstood you. HTH