I am create creating an engine, to connect my LS server using the following code.

Code:
public native static void init(String username, String password)
	/*-{
		$wnd.user_name = username;		
		var divTag = document.createElement("div");
		divTag.id = "list";

		divTag.setAttribute("class","ClassName");
		divTag.setAttribute("source","lightstreamer");
		divTag.setAttribute("table","TableName");
		divTag.setAttribute("item",username+"#TableName");
		divTag.setAttribute("field","FieldName");
		divTag.style.display = 'none'; 
		document.body.appendChild(divTag);

		$wnd.page = new $wnd.PushPage();
		$wnd.page.context.setDomain("chellasoftapp.com"); 
		$wnd.page.onEngineCreation = function(engine) {
			$wnd.lsEngine = engine;

			engine.connection.setLSHost("domainName.com"); 
			engine.connection.setLSPort("port"); 
			
			engine.connection.setAdapterName("AdapterName");						

			engine.connection.setUserName(username);
			engine.connection.setPassword(password);

			engine.changeStatus("STREAMING");
		}

		$wnd.page.bind();		
		$wnd.page.createEngine("AdapterName", "LS", "SHARE_SESSION", true);

		var itemName = username+"#iTableName";
		$wnd.pushtable = new $wnd.NonVisualTable(itemName, new Array("TableName"), "DISTINCT");
		$wnd.chellaSoft = this;
		$wnd.pushtable.onItemUpdate = function (item, updateInfo) {
			$wnd.jsonUpdatedStaticJS(updateInfo.getNewValue("FieldName"));
		}

		$wnd.page.addTable($wnd.pushtable, "TableName");
	}-*/;
While I am login it throws an error message states that "ER GroupListDescriptor Item names cannot be empty"

What do i need to do, for this exception, And where do i need make the changes either client side or Server side?

Thank you in advance