I m test driving Seam 2.3 on Jboss 6.1 , when i attempt to load the application i always get

Caused by: java.lang.ClassNotFoundException: org.hibernate.engine.spi.SessionImplementor

          at java.net.URLClassLoader$1.run(URLClassLoader.java:202) [:1.6.0_31]

          at java.security.AccessController.doPrivileged(Native Method) [:1.6.0_31]

          at java.net.URLClassLoader.findClass(URLClassLoader.java:190) [:1.6.0_31]

          at java.lang.ClassLoader.loadClass(ClassLoader.java:306) [:1.6.0_31]

          at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) [:1.6.0_31]

          at java.lang.ClassLoader.loadClass(ClassLoader.java:247) [:1.6.0_31]

          at java.lang.Class.forName0(Native Method) [:1.6.0_31]

          at java.lang.Class.forName(Class.java:247) [:1.6.0_31]

          at org.jboss.classloader.spi.base.BaseClassLoaderDomain.loadClass(BaseClassLoaderDomain.java:304) [jboss-classloader.jar:2.2.1.GA]

          at org.jboss.classloader.spi.base.BaseClassLoaderDomain.loadClass(BaseClassLoaderDomain.java:1172) [jboss-classloader.jar:2.2.1.GA]

          at org.jboss.classloader.spi.base.BaseClassLoader.loadClassFromDomain(BaseClassLoader.java:886) [jboss-classloader.jar:2.2.1.GA]

          at org.jboss.classloader.spi.base.BaseClassLoader.doLoadClass(BaseClassLoader.java:505) [jboss-classloader.jar:2.2.1.GA]

          at org.jboss.classloader.spi.base.BaseClassLoader.loadClass(BaseClassLoader.java:450) [jboss-classloader.jar:2.2.1.GA]

          at java.lang.ClassLoader.loadClass(ClassLoader.java:247) [:1.6.0_31]

          ... 258 more

Please how do i resolve this, I know Jboss6.1 comes with its own Hibernate Jars