wrong scale value!! for sp

[pollux0]

I m getting a wrong scale value error message when executing a sql stored proc from as asp page I know there should be a fourth parameter like:
("@totalTotal", addecimal, adParamOutput, 30,2)
but I get errors. thanks in advance!

**********ASP*********************
set objParameter9 = objCommand.createParameter ("@totalTotal", addecimal, adParamOutput)

objCommand.parameters.append objParameter9
*******************************

in the sp, the parameter is

**********SQL*********************
CREATE PROCEDURE createInvoice
@totalTotal decimal(30,2) output
AS....
*******************************