dwr数组作为参数报错

script
       var fatherO = new Array();
       var childO = new Array();
       InfoSourceManager.copyInfosource(fatherO,childO,back)

java
    copyInfosource(String parentKeyword[],String childcode[])

报错
IllegalArgumentException: Missing bean opener: { at uk.ltd.getahead.dwr.convert.BeanConverter.convertInbound(BeanConverter.java:133) at uk.ltd.getahead.dwr.impl.DefaultConverterManager.convertInbound(DefaultConverterManager.java:137) at ...

  查了DWR文档上面说数组可以直接传,在DWR测试页面 ,下面这种参数才可以访问到java类 
  InfoSourceManager.copyInfosource(["dd"]["dd"],["dd"]["dd"])

  不知为什么???????????