JBoss og MySQL - TransactionRolledbackException: Unable to commit

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11:53:46,122 INFO  [STDOUT] ProductEJB: --> ejbCreate()
11:53:46,132 INFO  [STDOUT] ProductEJB: --> ejbPostCreate()
11:53:46,132 INFO  [STDOUT] CategoryEJB -->ejbLoad
11:53:46,132 INFO  [STDOUT] ProductEJB -->ejbStore
11:53:46,132 INFO  [STDOUT] CategoryEJB -->ejbStore
11:53:46,143 ERROR [LogInterceptor] TransactionRolledbackException in method: public abstract void webshop.interfaces.AdminFacade.addProduct(webshop.vo.ProductVO) throws javax.ejb.CreateException,javax.ejb.FinderException,java.rmi.RemoteException, causedBy:
org.jboss.tm.JBossRollbackException: Unable to commit, tx=TransactionImpl:XidImpl[FormatId=257, GlobalId=laptop/174, BranchQual=, localId=174] status=STATUS_NO_TRANSACTION; - nested throwable: (javax.ejb.EJBException: Update failed. Expected one affected row: rowsAffected=0, id=)
    at org.jboss.tm.TransactionImpl.commit(TransactionImpl.java:344)
    at org.jboss.ejb.plugins.TxInterceptorCMT.endTransaction(TxInterceptorCMT.java:454)
    at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptorCMT.java:322)
    at org.jboss.ejb.plugins.TxInterceptorCMT.invoke(TxInterceptorCMT.java:146)
    at org.jboss.ejb.plugins.SecurityInterceptor.invoke(SecurityInterceptor.java:122)
    at org.jboss.ejb.plugins.LogInterceptor.invoke(LogInterceptor.java:192)
    at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(ProxyFactoryFinderInterceptor.java:122)
    at org.jboss.ejb.SessionContainer.internalInvoke(SessionContainer.java:624)
    at org.jboss.ejb.Container.invoke(Container.java:870)
    at sun.reflect.GeneratedMethodAccessor194.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:324)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:144)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:80)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:72)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:249)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:642)
    at org.jboss.invocation.jrmp.server.JRMPInvoker$MBeanServerAction.invoke(JRMPInvoker.java:805)
    at org.jboss.invocation.jrmp.server.JRMPInvoker.invoke(JRMPInvoker.java:406)
    at sun.reflect.GeneratedMethodAccessor92.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:324)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
    at sun.rmi.transport.Transport$1.run(Transport.java:148)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
    at java.lang.Thread.run(Thread.java:534)
Caused by: javax.ejb.EJBException: Update failed. Expected one affected row: rowsAffected=0, id=
    at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreEntityCommand.execute(JDBCStoreEntityCommand.java:155)
    at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.storeEntity(JDBCStoreManager.java:651)
    at org.jboss.ejb.plugins.CMPPersistenceManager.storeEntity(CMPPersistenceManager.java:413)
    at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.storeEntity(CachedConnectionInterceptor.java:390)
    at org.jboss.ejb.EntityContainer.storeEntity(EntityContainer.java:743)
    at org.jboss.ejb.GlobalTxEntityMap$2.synchronize(GlobalTxEntityMap.java:134)
    at org.jboss.ejb.GlobalTxEntityMap$GlobalTxSynchronization.synchronize(GlobalTxEntityMap.java:253)
    at org.jboss.ejb.GlobalTxEntityMap$GlobalTxSynchronization.beforeCompletion(GlobalTxEntityMap.java:302)
    at org.jboss.tm.TransactionImpl.doBeforeCompletion(TransactionImpl.java:1383)
    at org.jboss.tm.TransactionImpl.beforePrepare(TransactionImpl.java:1075)
    at org.jboss.tm.TransactionImpl.commit(TransactionImpl.java:296)
    ... 28 more