Can you post the error message ? would be useful...
seems that somehing in your portlet's wrong
Did you get an answer to your question? I have the same problem.
Although I will like to share what I learned from the problem. I deployed 1 portlet in a war file and everything works fine but when I try to deploy 2 portlets in a .war file both of them are registered and show up in the menu but when clicked show blank page.
It will be nice to get an answer to this one.