请教:在jsp中调用oracle函数出错.急!

我在jsp页面中写了如下代码:

sqlStr = "select distinct substr(tcidpk,0,"+String.valueOf(level*2)+") as tcidpk," +" getStrByClass(tcname,"+String.valueOf(level)+") as tcname " +" from tclassification where tcidpk like 'St%' ";

运行时出现如下错误:java.sql.SQLException: ORA-06575: 程序包或函数 GETSTRBYCLASS 处于无效状态

请问高手我是不是哪里没有配置好?