I downloaded 2.4CR3 and am running with JBoss 4.0.4GA and MySQL 4.1. It appears that the CMS portlet is having problems. I get this exception:

2006-08-04 09:24:59,142 DEBUG [org.jboss.system.ServiceController] starting service portal:service=CMS
2006-08-04 09:24:59,142 DEBUG [org.jboss.portal.cms.impl.jcr.JCRCMS] Starting portal:service=CMS
2006-08-04 09:24:59,142 INFO [org.jboss.portal.cms.impl.jcr.JCRCMS] Starting JCR CMS
2006-08-04 09:24:59,173 DEBUG [org.jboss.portal.cms.impl.jcr.JCRCMS] Jackrabbit configuration : <Repository>
 --lines deleted--
 </Repository>

2006-08-04 09:24:59,376 INFO [org.apache.jackrabbit.core.RepositoryImpl] Starting repository...
2006-08-04 09:24:59,626 WARN [org.jboss.resource.connectionmanager.TxConnectionManager] Connection error occured: org.jboss.resource.connectionmanager.TxConnectionManager$TxConnectionEventListener@b1fba0[state=NORMAL mc=org.jboss.resource.adapter.jdbc.local.LocalManagedConnection@105f759 handles=1 lastUse=1154708699626 permit=true trackByTx=true mcp=org.jboss.resource.connectionmanager.JBossManagedConnectionPool$OnePool@b2311b context=org.jboss.resource.connectionmanager.InternalManagedConnectionPool@b5f87c xaResource=org.jboss.resource.connectionmanager.TxConnectionManager$LocalXAResource@ccbb35 txSync=null]
java.lang.ArrayIndexOutOfBoundsException
 at java.lang.System.arraycopy(Native Method)
 at org.jboss.portal.jems.hibernate.ByteArrayBlob.getBytes(ByteArrayBlob.java:74)
 at com.mysql.jdbc.PreparedStatement.setBlob(PreparedStatement.java:1845)
 at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.setBlob(WrappedPreparedStatement.java:517)
 at org.jboss.portal.jems.hibernate.CacheableBlobUserType.nullSafeSet(CacheableBlobUserType.java:97)
 at org.hibernate.type.CustomType.nullSafeSet(CustomType.java:145)
 at org.hibernate.persister.entity.AbstractEntityPersister.dehydrate(AbstractEntityPersister.java:1910)
 --- lines deleted ---
 at org.hibernate.impl.SessionImpl.save(SessionImpl.java:521)
 at org.jboss.portal.cms.hibernate.HibernateStore$1.close(HibernateStore.java:1049)
 at sun.nio.cs.StreamEncoder$ConverterSE.implClose(StreamEncoder.java:261)
 at sun.nio.cs.StreamEncoder.close(StreamEncoder.java:160)
 at java.io.OutputStreamWriter.close(OutputStreamWriter.java:222)
 at org.apache.jackrabbit.core.RepositoryImpl.loadRootNodeId(RepositoryImpl.java:429)
 at org.apache.jackrabbit.core.RepositoryImpl.<init>(RepositoryImpl.java:214)
 at org.apache.jackrabbit.core.RepositoryImpl.create(RepositoryImpl.java:483)
 at org.jboss.portal.cms.impl.jcr.jackrabbit.JackrabbitJCRService.start(JackrabbitJCRService.java:102)
 at org.jboss.portal.cms.impl.jcr.JCRCMS.startJCR(JCRCMS.java:200)
 at org.jboss.portal.cms.impl.jcr.JCRCMS.startService(JCRCMS.java:167)
 at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289)
 at org.jboss.system.ServiceMBeanSupport.start(ServiceMBeanSupport.java:196)
 at org.jboss.portal.common.system.AbstractJBossService.start(AbstractJBossService.java:72)
 at sun.reflect.GeneratedMethodAccessor18.invoke(Unknown Source)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:324)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 --- lines deleted ---
 at org.jboss.deployment.SARDeployer.start(SARDeployer.java:302)
 at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1007)
 at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:808)
 at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:771)
 at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:755)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:324)
 at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
 at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
 at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
 at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
 at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
 at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
 at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
 at $Proxy5.deploy(Unknown Source)
 at org.jboss.system.server.ServerImpl.doStart(ServerImpl.java:482)
 at org.jboss.system.server.ServerImpl.start(ServerImpl.java:362)
 at org.jboss.Main.boot(Main.java:200)
 at org.jboss.Main$1.run(Main.java:464)
 at java.lang.Thread.run(Thread.java:534)
2006-08-04 09:24:59,641 DEBUG [org.jboss.util.NestedThrowable] org.jboss.util.NestedThrowable.parentTraceEnabled=true

I can still access the portal, but the CMS portlet windows show an NPE, the rest of the portlets work fine.

I had downloaded and used the CVS source for 2.4 just two weeks ago and that worked fine, as did 2.4CR2. I used MySQL 4.1 and 5.0, and even tried this on two different computers using two separate downloads.