I downloaded and unzipped 5.0 beta 2 to a WINXP box.
I am using java 6 update 1.

when I execute run.bat, I see

13:17:12,710 ERROR [AbstractKernelController] Error installing to Instantiated: name=DeploymentFilter state=Described
java.lang.IllegalStateException: Class not found: [Ljava.lang.String;
 at org.jboss.metadata.spi.signature.Signature.stringsToClasses(Signature.java:174)
 at org.jboss.metadata.spi.signature.Signature.stringsToClasses(Signature.java:125)
 at org.jboss.metadata.spi.signature.Signature.getParametersTypes(Signature.java:292)