Query showing error in Jaspersoft, not in cmd

cast(Sum(CODE21) as  Decimal(30,3))

shows error at Decimal(30,3) , ERROR : mismatched input '30' expecting RULE_INT

but when running on cmd it doesn't show any error. How to resolve this problem? Please Help.

P.S I'm using db2 and Jaspersoft Studio 6.3.0 Professional.