This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
What is the problem? Ajax within a portlet is very similar to Ajax in a Servlet/JSP application. Only thing is, ifyou're calling a Servlet or JSP resource, it must be packaged within the same war file. Maybe that's your issue?