Instantiating module File could not be added at URL - Sandbox solution

The file Benefit.aspx looks like this:

<%@ Page Inherits="Microsoft.SharePoint.Publishing.TemplateRedirectionPage,Microsoft.SharePoint.Publishing,Version=14.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c" %> 
<%@ Reference VirtualPath="~TemplatePageUrl" %> 
<%@ Reference VirtualPath="~masterurl/custom.master" %>

---

Caroline