Error accessing SimplePooledConnection. Connection has been invalidated

[stevem]

Can you mix DAO implementations?  I am in a restrictive Oracle environment that prevents me from deploying the Default CLOB support using the Oracle 10 JDBC drivers (which works great, by the way).  The client's servers still have Oracle 8i drivers (go figure).  I re-wrote the affected DAO as a JDBC DAO, but the code (below) results in the attached error.  I'm not finding much help on the web.  I tried changing to a JDBC transaction manager, but that broke my SqlMap DAOs.

    private void insert(ProductRequirement pr) {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            daoManager.startTransaction();
            conn = getConnection();          
            StringBuffer sql = new StringBuffer("INSERT INTO ");
            sql.append(" PRL_PRODUCT_REQ (PRODUCT_REQ_ID, DESCRIPTION, FILING_TYPES, PRODUCT_ID, ");
            sql.append(" PRODUCT_REQ_CAT_ID, PRL_STATE_ID, DATE_LAST_MODIFIED, USER_LAST_MODIFIED, ");
            sql.append(" DATE_CREATED, USER_CREATED) ");
            sql.append(" VALUES (?, EMPTY_CLOB(), ?, ?, ?, ?, ?, ?, ?, ?)");
             stmt = conn.prepareStatement(sql.toString());  <-- Fails here

com.ibatis.common.exception.NestedRuntimeException: Error accessing SimplePooledConnection.  Connection has been invalidated (probably released back to the pool).
    at com.ibatis.common.jdbc.SimpleDataSource$SimplePooledConnection.getValidConnection(SimpleDataSource.java:901)
    at com.ibatis.common.jdbc.SimpleDataSource$SimplePooledConnection.invoke(SimpleDataSource.java:946)
    at $Proxy8.prepareStatement(Unknown Source)
    at com.serff.prl.dao.impl.OracleJdbcProductRequirementDAO.insert(OracleJdbcProductRequirementDAO.java:224)
    at com.serff.prl.dao.impl.OracleJdbcProductRequirementDAO.saveOrUpdate(OracleJdbcProductRequirementDAO.java:154)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.ibatis.dao.engine.impl.DaoProxy.invoke(DaoProxy.java:72)
    at $Proxy6.saveOrUpdate(Unknown Source)
    at com.serff.prl.dao.ProductRequirementTest.testProductRequirementCRUD(ProductRequirementTest.java:176)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at junit.framework.TestCase.runTest(TestCase.java:154)
    at junit.framework.TestCase.runBare(TestCase.java:127)
    at junit.framework.TestResult$1.protect(TestResult.java:106)
    at junit.framework.TestResult.runProtected(TestResult.java:124)
    at junit.framework.TestResult.run(TestResult.java:109)
    at junit.framework.TestCase.run(TestCase.java:118)
    at junit.framework.TestSuite.runTest(TestSuite.java:208)
    at junit.framework.TestSuite.run(TestSuite.java:203)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:421)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:305)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:186)