Is your WAR deployed to
JBoss AS? If so, remove the JBoss-related JAR files from the WEB-INF/lib directory - those JARs are already provided by JBoss AS.
If the WAR is not deployed to JBoss AS, you need to add the jboss-security-spi.jar file (assuming you are running 5.1.0 or 6.0.x)
Which version of JBoss AS?