JBoss ON installation fails with error No ClassLoaders found for: oracle.jdbc.xa.client.OracleXADatasource

Issue

We have the following settings in rhq-server.properties:

* Database
rhq.server.database.connection-url=jdbc:oracle:thin:@[database_ip]:[database_port]:JBDB
rhq.server.database.driver-class=oracle.jdbc.driver.OracleDriver
rhq.server.database.xa-datasource-class=oracle.jdbc.xa.client.OracleXADatasource
rhq.server.database.user-name=[user_name]
rhq.server.database.password=3eefda5ae5f158077e6930fec57d49fc0a4cfca68dc7a59
rhq.server.database.type-mapping=Oracle
rhq.server.database.server-name=
rhq.server.database.port=
rhq.server.database.db-name=
hibernate.dialect=org.hibernate.dialect.Oracle10gDialect
...

When we try to silently install JBoss ON, installation fails with the following error messages in the rhq-server-log4j.log file:

INFO  [org.apache.catalina.core.ContainerBase] Autoinstaller Servlet: Server has been auto-installed and should be ready shortly.
INFO  [org.apache.coyote.http11.Http11Protocol] Starting Coyote HTTP/1.1 on http-0.0.0.0-7080
INFO  [org.apache.coyote.http11.Http11Protocol] Starting Coyote HTTP/1.1 on http-0.0.0.0-7443
INFO  [org.jboss.system.server.Server] JBoss (MX MicroKernel) [4.2.3.GA (build: SVNTag=JBoss_4_2_3_GA date=200807181417)] Started in 28s:264ms
INFO  [org.jboss.mail.MailService] Mail Service bound to java:/Mail
INFO  [org.jboss.resource.connectionmanager.ConnectionFactoryBindingService] Bound ConnectionManager 'jboss.jca:service=ConnectionFactoryBinding,name=JmsXA' to JNDI name 'java:JmsXA'
INFO  [org.jboss.resource.connectionmanager.ConnectionFactoryBindingService] Bound ConnectionManager 'jboss.jca:service=DataSourceBinding,name=RHQDS' to JNDI name 'java:RHQDS'
WARN  [org.jboss.resource.connectionmanager.JBossManagedConnectionPool] Throwable while attempting to get a new connection: null
org.jboss.resource.JBossResourceException: Could not create connection; - nested throwable: (org.jboss.resource.JBossResourceException: Class not found for XADataSource oracle.jdbc.xa.client.OracleXADatasource; - nested throwable: (java.lang.ClassNotFoundException: No ClassLoaders found for: oracle.jdbc.xa.client.OracleXADatasource))