Append after the html:form
close tag the next code and try:
<logic:present name="account_bean" property="error">
<div>
<link rel="stylesheet" href="//code.jquery.com/ui/1.10.3/themes/smoothness/jquery-ui.css">
<script src="//code.jquery.com/jquery-1.9.1.js"></script>
<script src="//code.jquery.com/ui/1.10.3/jquery-ui.js"></script>
<script>
// When DOM is ready
$(function() {
$("#errorDialog").dialog({
title: "Login",
autoOpen: false,
resizable: false,
show: "clip",
hide: "clip",
modal: true,
dialogClass: "ui-state-active"
});
});
// When Window is ready
$(window).load(function() {
$("#errorDialog").dialog("open");
});
</script>
<div id="errorDialog">
<bean:write name="account_bean" property="error" filter="false"/>
</div>
</div>
</logic:present>