elRTE

When I try to locate div of elrte in a div which's style="display:none", I'm getting error in firefox-5 as

" 
Error: uncaught exception: [Exception... 
"Component returned failure code: 0x80004005 
(NS_ERROR_FAILURE) [nsIDOMNSHTMLDocument.execCommand]"  
nsresult: "0x80004005 
(NS_ERROR_FAILURE)"  
location: "JS frame :: http://localhost/mypage/admin/elrte/js/elrte.min.js
 :: <TOP_LEVEL> :: line 34"  data: no]
" 

here is my code,

<script type="text/javascript" charset="utf-8">
        $(document).ready(function() {
            var opts = {
                cssClass : 'el-rte',
                // lang     : 'ru',
                height   : 450,
                width    : 740,
                toolbar  : 'complete',
                cssfiles : ['elrte/css/elrte-inner.css']
            }
            $('#box').elrte(opts);
        });
    </script>
<div style="display:none">
<div id="box"></div>
</div>