Logger error

[Carles Duque]

Hello, I'm using tomcat and ojb. I test an example of cocoon with ojb:

        PersistenceManager manager = factory.getPersistenceManager();
        /* 2. Get current transaction */
        Transaction tx = manager.currentTransaction();
        /* 3. Start a Transaction */
        tx.begin();
        /* 4. now perform persistence operations. Store the new user */
        manager.makePersistent(usr);
        /* 5. Commit the transaction  */
      tx.commit();


In the "tx.begin();" tha application throws an error like this:
        [BOOT] ERROR: [org.apache.ojb.broker.util.logging.LoggerFactoryImpl]
Could not set logger for class null
        org/apache/commons/lang/exception/NestableException
        java.lang.NoClassDefFoundError:
org/apache/commons/lang/exception/NestableException
        at java.lang.ClassLoader.defineClass0(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:509)


Can you help me?

Carles