If you don't already, you should have the JEE API bookmarked in your browser.
There is a link in my signature.
Cross context communication is not covered in great detail in the servlet spec so the implementation, across containers is, at best, inconsistent. I do know that the API (link that I gave you) specifies that the context name must start with a forward slash.
The given path must be begin with "/", is interpreted relative to the server's document root and is matched against the context roots of other web applications hosted on this container.
I also know that, in Tomcat, this feature is disabled by default for security reasons and has to be configured to work.
[ September 13, 2007: Message edited by: Ben Souther ]