When deploying 2 EARs containing each an ejb 2.x jar with the same name ("my-ejbs.jar") deployment fails with this stack trace when the second is handled by the EjbDeployer.
The BasicMBeanRegistry tries to register them both with the name "jboss.j2ee:module="my-ejbs.jar",service=EjbModule"

14:33:27,796 WARN [AbstractDeploymentContext] Unable to register deployment mbean jboss.j2ee:module="my-ejbs.jar",service=EjbModule
javax.management.InstanceAlreadyExistsException: jboss.deployment:id="jboss.j2ee:module="my-ejbs.jar",service=EjbModule",type=Component already registered.
at org.jboss.mx.server.registry.BasicMBeanRegistry.add(BasicMBeanRegistry.java:767)
at org.jboss.mx.server.registry.BasicMBeanRegistry.registerMBean(BasicMBeanRegistry.java:236)
at sun.reflect.GeneratedMethodAccessor89.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96)
at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:138)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:90)
at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:140)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:90)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668)
at org.jboss.mx.server.MBeanServerImpl$3.run(MBeanServerImpl.java:1431)
at java.security.AccessController.doPrivileged(Native Method)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:1426)
at org.jboss.mx.server.MBeanServerImpl.registerMBean(MBeanServerImpl.java:376)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentContext.registerMBeans(AbstractDeploymentContext.java:989)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentContext.addComponent(AbstractDeploymentContext.java:719)
at org.jboss.deployers.structure.spi.helpers.AbstractDeploymentUnit.addComponent(AbstractDeploymentUnit.java:249)
at org.jboss.system.deployers.ServiceDeploymentDeployer.addServiceComponent(ServiceDeploymentDeployer.java:62)
at org.jboss.system.deployers.ServiceDeploymentDeployer$ServiceMetaDataVisitor.deploy(ServiceDeploymentDeployer.java:150)
at org.jboss.system.deployers.ServiceDeploymentDeployer$ServiceMetaDataVisitor.deploy(ServiceDeploymentDeployer.java:141)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.deploy(AbstractRealDeployerWithInput.java:125)
at org.jboss.deployers.spi.deployer.helpers.AbstractComponentDeployer.deployComponents(AbstractComponentDeployer.java:102)
at org.jboss.deployers.spi.deployer.helpers.AbstractComponentDeployer.internalDeploy(AbstractComponentDeployer.java:82)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50)
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1210)
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1598)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1062)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781)
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:545)
at org.jboss.system.server.profileservice.ProfileServiceBootstrap.loadProfile(ProfileServiceBootstrap.java:304)
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)
14:33:27,828 INFO [TomcatDeployment] deploy, ctxPath=/abc-6-0-4, vfsUrl=my-ear-6-0-4.ear/webApp.war
14:33:28,046 WARN [TomcatDeployment] Failed to setup clustering, clustering disabled. NoClassDefFoundError: org/jboss/cache/pojo/jmx/PojoCacheJmxWrapperMBean
14:33:28,125 INFO [EjbModule] Deploying AbcSLS
14:33:28,203 INFO [ProxyFactory] Bound EJB Home 'AbcSLS' to jndi 'xyz/abc-6-0-4/internal/ejb/session/Abc'
14:33:28,218 INFO [ProxyFactory] Unbind EJB Home 'AbcSLS' from jndi 'xyz/abc-6-0-4/internal/ejb/session/Abc'
14:33:28,218 INFO [EjbModule] Undeployed AbcSLS
14:33:28,218 INFO [TomcatDeployment] undeploy, ctxPath=/abc-6-0-4, vfsUrl=my-ear-6-0-4.ear/webApp.war
14:33:31,015 ERROR [AbstractKernelController] Error installing to Real: name=vfsfile:/C:/develop/server/jboss-5.0.0.GA.JDK6/server/standard/deploy/my-ear-6-0-4.ear/ state=PreReal mode=Manual requiredState=Real
org.jboss.deployers.spi.DeploymentException: Error deploying: jboss.j2ee:service=EjbModule,module="my-ejbs.jar"
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49)
at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:123)
at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:45)
at org.jboss.deployers.spi.deployer.helpers.AbstractSimpleRealDeployer.internalDeploy(AbstractSimpleRealDeployer.java:62)
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:50)
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:171)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1439)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1157)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1178)
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1210)
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1098)
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:348)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:1598)
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:934)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1062)
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:984)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:822)
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:553)
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:781)
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:545)
at org.jboss.system.server.profileservice.ProfileServiceBootstrap.loadProfile(ProfileServiceBootstrap.java:304)
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.IllegalStateException: jboss.j2ee:module="my-ejbs.jar",service=EjbModule is already installed.
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:716)
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:540)
at org.jboss.system.ServiceController.doInstall(ServiceController.java:670)
at org.jboss.system.ServiceController.install(ServiceController.java:273)
at org.jboss.system.deployers.ServiceDeployer.deploy(ServiceDeployer.java:95)
... 24 more
14:33:31,093 ERROR [ProfileServiceBootstrap] Failed to load profile: Summary of incomplete deployments (SEE PREVIOUS ERRORS FOR DETAILS):

• • • CONTEXTS IN ERROR: Name -> Error

vfsfile:/C:/develop/server/jboss-5.0.0.GA.JDK6/server/standard/deploy/my-ear-6-0-4.ear/ -> java.lang.IllegalStateException: jboss.j2ee:module="my-ejbs.jar",service=EjbModule is already installed.

14:33:31,109 INFO [Http11Protocol] Starting Coyote HTTP/1.1 on http-127.0.0.1-8080
14:33:31,140 INFO [AjpProtocol] Starting Coyote AJP/1.3 on ajp-127.0.0.1-8009
14:33:31,140 INFO [ServerImpl] JBoss (Microcontainer) [5.0.0.GA (build: SVNTag=JBoss_5_0_0_GA date=200812042120)] Started in 1m:40s:531ms