I am unable to setup UserTransaction for JIRA.
I followed the steps described in the installation guide, for Tomcat 5, and at startup I get the following stacktrace in my logfile :

2004-08-26 14:25:53,992 WARN [core.entity.transaction.JNDIFactory] NamingException while finding UserTransaction named java:comp/UserTransaction in JNDI.
javax.naming.NamingException: Cannot create resource instance
at org.apache.naming.factory.TransactionFactory.getObjectInstance(TransactionFactory.java:98)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:301)
at org.apache.naming.NamingContext.lookup(NamingContext.java:791)
at org.apache.naming.NamingContext.lookup(NamingContext.java:138)
at org.apache.naming.NamingContext.lookup(NamingContext.java:779)
at org.apache.naming.NamingContext.lookup(NamingContext.java:151)
at org.apache.naming.SelectorContext.lookup(SelectorContext.java:136)
at javax.naming.InitialContext.lookup(InitialContext.java:347)
at org.ofbiz.core.entity.transaction.JNDIFactory.getUserTransaction(JNDIFactory.java:109)
at org.ofbiz.core.entity.TransactionFactory.getUserTransaction(TransactionFactory.java:91)
at org.ofbiz.core.entity.TransactionUtil.getStatus(TransactionUtil.java:78)
at org.ofbiz.core.entity.jdbc.SQLProcessor.getConnection(SQLProcessor.java:244)
at org.ofbiz.core.entity.jdbc.SQLProcessor.prepareStatement(SQLProcessor.java:283)
at org.ofbiz.core.entity.GenericDAO.selectListIteratorByCondition(GenericDAO.java:1024)
at org.ofbiz.core.entity.GenericDAO.selectByAnd(GenericDAO.java:595)
at org.ofbiz.core.entity.GenericHelperDAO.findByAnd(GenericHelperDAO.java:134)
at org.ofbiz.core.entity.GenericDelegator.findByAnd(GenericDelegator.java:782)
at org.ofbiz.core.entity.GenericDelegator.findByAnd(GenericDelegator.java:767)
at org.ofbiz.core.entity.GenericDelegator.findByAnd(GenericDelegator.java:744)
at com.opensymphony.module.propertyset.ofbiz.OFBizPropertySet.findPropertyEntry(OFBizPropertySet.java:223)
at com.opensymphony.module.propertyset.ofbiz.OFBizPropertySet.get(OFBizPropertySet.java:191)
at com.opensymphony.module.propertyset.AbstractPropertySet.getString(AbstractPropertySet.java:373)
at com.atlassian.jira.propertyset.JiraCachingPropertySet.getString(JiraCachingPropertySet.java:330)
at com.atlassian.jira.config.properties.ApplicationProperties.getString(ApplicationProperties.java:70)
at com.atlassian.jira.config.webwork.ApplicationPropertiesConfiguration.getImpl(ApplicationPropertiesConfiguration.java:29)
at webwork.config.DelegatingConfiguration.getImpl(DelegatingConfiguration.java:43)
at com.atlassian.jira.config.webwork.JiraConfiguration.getImpl(JiraConfiguration.java:38)
at webwork.config.Configuration.get(Configuration.java:42)
at webwork.config.Configuration.getString(Configuration.java:52)
at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.init(JiraServletDispatcher.java:143)
...

Note that the application seems to work, but it is sluggish and it fills my logfile.