I include rf 4 via maven and use it in jboss as 6 m5. Probably, both Weld and RF makes use of other versions of slf4j, so I get this error:

<properties>
      <!-- The version of Weld extensions in use -->
      <weld.extensions.version>1.0.0-CR2</weld.extensions.version>
      <org.richfaces.bom.version>4.0.0.20100826-M2</org.richfaces.bom.version>
   </properties>

DEPLOYMENTS IN ERROR:

  Deployment "vfs:///D:/jboss-6.0.0.20100721-M4/server/default/deploy/MES.war_WeldBootstrap" is in error due to the following reason(s): java.lang.LinkageError: loader constraint violation: when resolving method "org.slf4j.impl.StaticLoggerBinder.getLoggerFactory()Lorg/slf4j/ILoggerFactory;" the class loader (instance of org/jboss/classloader/spi/base/BaseClassLoader) of the current class, org/slf4j/LoggerFactory, and the class loader (instance of org/jboss/classloader/spi/base/BaseClassLoader) for resolved class, org/slf4j/impl/StaticLoggerBinder, have different Class objects for the type org/slf4j/ILoggerFactory used in the signature, **ERROR**

     at org.jboss.deployers.plugins.deployers.DeployersImpl.checkComplete(DeployersImpl.java:1228) [:2.2.0.Alpha6]

    at org.jboss.deployers.plugins.main.MainDeployerImpl.checkComplete(MainDeployerImpl.java:905) [:2.2.0.Alpha6]

    at org.jboss.system.server.profileservice.deployers.MainDeployerPlugin.checkComplete(MainDeployerPlugin.java:87) [:6.0.0.20100721-M4]

    at org.jboss.profileservice.deployment.ProfileDeployerPluginRegistry.checkAllComplete(ProfileDeployerPluginRegistry.java:118) [:0.1.0.Alpha1]

    at org.jboss.system.server.profileservice.bootstrap.BasicProfileServiceBootstrap.start(BasicProfileServiceBootstrap.java:133) [:6.0.0.20100721-M4]

    at org.jboss.system.server.profileservice.bootstrap.BasicProfileServiceBootstrap.start(BasicProfileServiceBootstrap.java:56) [:6.0.0.20100721-M4]

    at org.jboss.bootstrap.impl.base.server.AbstractServer.startBootstraps(AbstractServer.java:827) [jboss-bootstrap-impl-base.jar:2.1.0-alpha-5]

    at org.jboss.bootstrap.impl.base.server.AbstractServer$StartServerTask.run(AbstractServer.java:417) [jboss-bootstrap-impl-base.jar:2.1.0-alpha-5]

    at java.lang.Thread.run(Thread.java:619) [:1.6.0_21]

by excluding rf 4 libs, my application runs (but logically, without rf).

Is this a (known) bug?