IllegalStateException when using Seam REST

When I add Seam REST to my EAR I'm getting the following error at runtime:

16:20:11,838 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/swe1REST]] (http--127.0.0.1-8080-2) StandardWrapper.Throwable: java.lang.RuntimeException: Unable to instantiate InjectorFactory implementation.
at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:174) [resteasy-jaxrs-2.1.0.GA.jar:]
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.init(ServletContainerDispatcher.java:67) [resteasy-jaxrs-2.1.0.GA.jar:]
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.init(HttpServletDispatcher.java:36) [resteasy-jaxrs-2.1.0.GA.jar:]
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1202) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:952) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:188) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.jboss.as.web.NamingValve.invoke(NamingValve.java:57) [jboss-as-web-7.0.0.Beta4-SNAPSHOT.jar:7.0.0.Beta4-SNAPSHOT]
at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:49) [jboss-as-jpa-7.0.0.Beta4-SNAPSHOT.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:154) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:893) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:626) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:2054) [jbossweb-7.0.0.CR4.jar:7.0.0.Beta4-SNAPSHOT]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_26]
Caused by: java.lang.IllegalStateException: Unable to obtain ResteasyCdiExtension instance.
at org.jboss.resteasy.cdi.CdiInjectorFactory.lookupResteasyCdiExtension(CdiInjectorFactory.java:178) [resteasy-cdi-2.1.0.GA.jar:]
at org.jboss.resteasy.cdi.CdiInjectorFactory.<init>(CdiInjectorFactory.java:43) [resteasy-cdi-2.1.0.GA.jar:]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) [:1.6.0_26]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) [:1.6.0_26]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) [:1.6.0_26]
at java.lang.reflect.Constructor.newInstance(Constructor.java:513) [:1.6.0_26]
at java.lang.Class.newInstance0(Class.java:355) [:1.6.0_26]
at java.lang.Class.newInstance(Class.java:308) [:1.6.0_26]
at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:166) [resteasy-jaxrs-2.1.0.GA.jar:]
... 16 more