SSO ear deployment class cast exception

[adorandish]

Problem:
I downloaded the source for the JBoss SSO and followed the instruction given in: http://www.jboss.org/community/docs/DOC-12304

Environment:
OS: Windows Vista
JDK: 1.6.0_11
JBoss: JBoss-5.0.1.GA

Error:
here is the error I get when I start the jboss:

14:33:31,801 ERROR [ProfileServiceBootstrap] Failed to load profile:
org.jboss.deployers.spi.DeploymentException: Exception determining structure: AbstractVFSDeployment(jboss-federation-server.ear)
 at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49)
 at org.jboss.deployers.structure.spi.helpers.AbstractStructuralDeployers.determineStructure(AbstractStructuralDeployers.java:85)
 at org.jboss.deployers.plugins.main.MainDeployerImpl.determineStructure(MainDeployerImpl.java:1000)
 at org.jboss.deployers.plugins.main.MainDeployerImpl.determineDeploymentContext(MainDeployerImpl.java:440)
 at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:390)
 at org.jboss.deployers.plugins.main.MainDeployerImpl.addDeployment(MainDeployerImpl.java:300)
 at org.jboss.system.server.profileservice.ProfileServiceBootstrap.loadProfile(ProfileServiceBootstrap.java:303)
 at org.jboss.system.server.profileservice.ProfileServiceBootstrap.start(ProfileServiceBootstrap.java:205)
 at org.jboss.bootstrap.AbstractServerImpl.start(AbstractServerImpl.java:405)
 at org.jboss.Main.boot(Main.java:209)
 at org.jboss.Main$1.run(Main.java:547)
 at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.RuntimeException: Error determining structure: jboss-federation-server.ear
 at org.jboss.deployment.EARStructure.determineStructure(EARStructure.java:293)
 at org.jboss.deployers.vfs.plugins.structure.StructureDeployerWrapper.determineStructure(StructureDeployerWrapper.java:73)
 at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.doDetermineStructure(VFSStructuralDeployersImpl.java:196
 at org.jboss.deployers.vfs.plugins.structure.VFSStructuralDeployersImpl.determineStructure(VFSStructuralDeployersImpl.java:221)
 at org.jboss.deployers.structure.spi.helpers.AbstractStructuralDeployers.determineStructure(AbstractStructuralDeployers.java:77)
 ... 10 more
Caused by: java.lang.ClassCastException: org.jboss.metadata.ear.jboss.JBoss50DTDAppMetaData cannot be cast to org.jboss.metadata.ear.spe
 at org.jboss.deployment.EARStructure.determineStructure(EARStructure.java:160)
 ... 14 more
14:33:31,818 INFO [ServerImpl] JBoss (Microcontainer) [5.0.1.GA (build: SVNTag=JBoss_5_0_1_GA date=200902232048)] Started in 10s:491ms