You're using JSTL 1.0 (uri="http://java.sun.com/jstl/xml"), and the xml attribute of the parse tag does not accept expressions like EL.
Maybe you want to try JSTL1.1 (uri="http://java.sun.com/jsp/jstl/xml"), which accepts expressions. The xml attribute is deprecated in 1.1, so use the doc attribute instead.
Just posting a solution after googling about this problem. Hope you will solved your problem with the help from Josh Brown. This is what he wrote
If you're getting the error "According to TLD or attribute directive in tag file, attribute items does not accept any expressions.", you're probably using an outdated URI for the core tag library.
1.0 URI <%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
1.1 URI <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>