JIRA and Confluence do not coexist on Jetty 4.2.22

Apparently if JIRA and Confluence are deployed in the same Jetty instance, two instances of the JNDI jars are loaded, causing an error. JRA-4802.

I have installed JIRA 2.6.1 on Jetty 4.2.22 but it failed to run. My database is PostgreSQL 8.0b3. I followed the Jetty install doc to download the extra jars, modified entityengine.xml. When Jetty starts the JIRA context, I get the following errors:

23:27:49.187 EVENT file:/opt/jetty-4.2.22/webapps/jira/ anti-aliased to file:/opt/jira-professional-2.6.1/deployed-war/
23:27:49.983 EVENT Started WebApplicationContext[/jira,Atlassian JIRA Web Application]
2004-10-03 23:27:50,705 WARN [atlassian.jira.upgrade.ConsistencyCheckImpl] Detected that you are using Tomcat or Websphere - turned off all transactions.
2004-10-03 23:27:51,604 ERROR [NoModule]
java.lang.SecurityException: sealing violation: can't seal package javax.naming: already loaded
at java.net.URLClassLoader.defineClass(URLClassLoader.java:234)
at java.net.URLClassLoader.access$100(URLClassLoader.java:55)
at java.net.URLClassLoader$1.run(URLClassLoader.java:194)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at org.mortbay.http.ContextLoader.loadClass(ContextLoader.java:197)
at org.mortbay.http.ContextLoader.loadClass(ContextLoader.java:170)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:1610)
at java.lang.Class.getConstructor0(Class.java:1922)
at java.lang.Class.newInstance0(Class.java:278)
at java.lang.Class.newInstance(Class.java:261)
at org.ofbiz.core.entity.TransactionFactory.getTransactionFactory(TransactionFactory.java:68)
at org.ofbiz.core.entity.TransactionFactory.getConnection(TransactionFactory.java:99)
at org.ofbiz.core.entity.ConnectionFactory.getConnection(ConnectionFactory.java:53)
...

Here here all Jetty's jars upon the request of Scott:

[root@hebron (/opt/jetty)]# find . -name "*.jar"
./ext/ant.jar
./ext/jasper-compiler.jar
./ext/jasper-runtime.jar
./ext/jcert.jar
./ext/jmxri.jar
./ext/jmxtools.jar
./ext/jnet.jar
./ext/jsse.jar
./ext/xercesImpl.jar
./ext/xml-apis.jar
./lib/javax.servlet.jar
./lib/org.mortbay.jetty.jar
./lib/org.mortbay.jmx.jar
./extra/lib/org.mortbay.jetty-jdk1.2.jar
./extra/lib/org.mortbay.jmx-jdk1.2.jar
./start.jar
./stop.jar