unable to load SWC automation.swc

I'm trying to use FDS on JBoss. I unzipped flex.zip into flex.war. I deployed the directory flex.war to JBoss, I created a "Hello, World" FDS project using Flex Builder. I specified "compile on server".

In the "Problems" window in Flex Builder I get the error "unable to load SWC automation.swc.

automation.swc does exist in the deployed flex.war in WEB-INF/flex/libs

Any ideas what the problem is?