I know what caused the "Oveflow problem. I used Cint function in the SQL statement to convert the result from single to integer for calculated field. This field needs to be integer in the report. By using CInt function it generated this error.
One of the fields I used to do the calculation has these properties in the table: Single, Percent. Therefore, the result field produce a float value. I want to convert this value to integer. But I don't see why this will give me error when the result is a calculated field?