executeBatch()的问题，急啊！！望高手指教

StringBuffer sbInsert = new StringBuffer(); 
sbInsert.append("insert into t_wtbs_whitelist ");
sbInsert.append("(ID,sptype,spname,spurl_type,url,creator,create_time,update_user,update_time) ");
sbInsert.append("values (SEQ_WTBS_WHITELIST.nextval,'?','?','?','?','?',to_date('?','yyyy-MM-dd hh24:mi:ss'),'?',to_date('?','yyyy-MM-dd hh24:mi:ss'))");
preInsert = conn.prepareStatement(sbInsert.toString());

for(int i = 0; i < wtbslist.size(); i++)
{
wvo  = (WtbsVO)wtbslist.get(i);
preInsert.setString(1, wvo.getSpType());
preInsert.setString(2, wvo.getSpName());
preInsert.setString(3, wvo.getSpUrlType());
preInsert.setString(4, wvo.getUrl());
preInsert.setString(5, "youlong");
preInsert.setString(6, importTime);
preInsert.setString(7, "administrator");
preInsert.setString(8, importTime);
preInsert.addBatch();
System.out.println("添加数据: "+sbInsert.toString());
}

int [] i = preInsert.executeBatch(); //  每次就是到这以行出错，请大家帮我看看，急啊。！！！
System.out.println(i.length);
conn.commit(); //执行成功则提交
isSuccess = true;