We have been Jboss 3.2.3 for sometime and have
recently been going through an upgrade to Jboss 4.0.5GA.

Under the old environment, we have a very solid deployment, with no
downtime (other than for regular updates to code) for about 2 year. We
have just got through this upgrade and are now getting two or three
very strange, and fatal errors.

Below is an example of one of them - It is thrown from both CMP Entity
Bean Finder methods as well as from DAO lookups i.e. at some points the same code succeeds or fails withi this error, which makes me think that there is some wrong with
the connection pool/driver/transactions settings for Jboss. So I
want to get some help to know to where to being looking for the
issue:

[org.jboss.ejb.plugins.cmp.jdbc.JDBCEJBQLQuery.Syst emMessage#findCurrentForUserByType]
Find failed
org.jboss.util.NestedSQLException: Transaction is not active:
tx=TransactionImpl:XidImpl[FormatId=257,
GlobalId=demo.scheduleexpress.com/9552, BranchQual=, localId=9552]; -
nested throwable: (javax.resource.ResourceException: Transaction is not
active: tx=TransactionImpl:XidImpl[FormatId=257,
GlobalId=demo.scheduleexpress.com/9552, BranchQual=, localId=9552])
at
org.jboss.resource.adapter.jdbc.WrapperDataSource. getConnection(WrapperDataSource.java:79)
at
org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCo mmand.execute(JDBCAbstractQueryCommand.java:210)
at
org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCo mmand.execute(JDBCAbstractQueryCommand.java:128)
at
org.jboss.ejb.plugins.cmp.jdbc.JDBCFindEntitiesCom mand.execute(JDBCFindEntitiesCommand.java:40)
at
org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.fi ndEntities(JDBCStoreManager.java:598)
at
org.jboss.ejb.plugins.CMPPersistenceManager.findEn tities(CMPPersistenceManager.java:322)
at
org.jboss.resource.connectionmanager.CachedConnect ionInterceptor.findEntities(CachedConnectionInterc eptor.java:245)
at
org.jboss.ejb.EntityContainer.findLocal(EntityCont ainer.java:649)

I have no idea why this would occurr,