Liferay 6.2 has no longer supports the aui-dialog, aui-io etc,but all of them deprecated in 6.2. We need to use below mentioned AUI JS modules :
http://www.liferay.com/documentation/liferay-portal/6.2/development/-/ai/alloyui-2-0-bootstrap-migration-liferay-portal-6-2-dev-guide-02-en
login_popup.jsp
<%@ taglib uri="http://liferay.com/tld/portlet" prefix="liferay-portlet" %>
<liferay-portlet:renderURL portletName="58" var="loginPortletURL" windowState="<%=LiferayWindowState.POP_UP.toString()%>">
</liferay-portlet:renderURL>
<aui:button name="login-popup" id="login-popup" value="login"> </aui:button>
<aui:script>
AUI().use('aui-base','liferay-util-window','aui-io-plugin-deprecated',function(A){
A.one('#<portlet:namespace/>login-popup').on('click', function(event){
var login_popup= Liferay.Util.Window.getWindow(
{
dialog: {
centered: true,
constrain2view: true,
modal: true,
resizable: false,
width: 475
}
}).plug(A.Plugin.DialogIframe,
{
autoLoad: true,
iframeCssClass: 'dialog-iframe',
uri:'<%=loginPortletURL.toString()%>'
}).render();
login_popup.show();
login_popup.titleNode.html("Login");
});
});
</aui:script>