Any ideas why I would be getting this?

Caused by: java.lang.LinkageError: loader constraint violation: when resolving method "javax.faces.context.FacesContext.getELContext()Ljavax/el/ELContext;" the class loader (instance of org/jboss/web/tomcat/service/WebAppClassLoader) of the current class, com/sun/facelets/el/ELAdaptor, and the class loader (instance of org/jboss/mx/loading/UnifiedClassLoader3) for resolved class, javax/faces/context/FacesContext, have different Class objects for the type javax/el/ELContext used in the signature
at com.sun.facelets.el.ELAdaptor.getELContext(ELAdaptor.java:45)
at com.sun.facelets.impl.DefaultFaceletContext.(DefaultFaceletContext.java:86)
at com.sun.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:91)
at org.jboss.seam.debug.jsf.SeamDebugPhaseListener.beforePhase(SeamDebugPhaseListener.java:46)
at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:222)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
... 33 more