Erro ao inserir dados (JPA, JSF, Glassfish)

Bom dia a todos, estamos desenvolvendo uma aplicação web, utilizando jsf2, jpa+glassfish, eclipse, o curioso é que quando eu tento inserir dados no B.D, via aplicação dá o seguinte erro abaixo.
Então vamos -lá, para alterar, fazer select e remove funciona normalmente, o problema é só na hora de inserir dados.
Outra coisa muito estranha, quando troco de pc, coloco com as mesmas configurações e o mesmo código(ou seja, pego o código, instalo o eclipse, glassfish, b.d. que é o mysql 5.5, funciona normalmente). Alguem tem alguma sugestão?

Obrigado.

Informações: Hibernate: insert into pais (nome) values (?)

Advertência: EJB5184:A system exception occurred during an invocation on EJB PaisDao, method: public void br.com.autsystem.dao.NFEletronicaDao.inserir(java.lang.Object)

Advertência: javax.ejb.EJBException

at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5215)

at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5113)

at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4901)

at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2045)

at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1994)

at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)

at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)

at $Proxy140.inserir(Unknown Source)

at br.com.autsystem.dao.EJB31_Generated__PaisDao__Intf____Bean.inserir(Unknown Source)

at br.com.autsystem.form.PaisForm.gravar(PaisForm.java:89)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:601)

at com.sun.el.parser.AstValue.invoke(AstValue.java:254)

at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:302)

at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)

at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)

at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)

at javax.faces.component.UICommand.broadcast(UICommand.java:315)

at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)

at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)

at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)

at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)

at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)

at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)

at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1542)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)

at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)

at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)

at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)

at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)

at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)

at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)

at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)

at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)

at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)

at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)

at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)

at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)

at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)

at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)

at com.sun.grizzly.ContextTask.run(ContextTask.java:71)

at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)

at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)

at java.lang.Thread.run(Thread.java:722)

Caused by: java.lang.NullPointerException

at com.sun.gjc.spi.base.PreparedStatementWrapper.close(PreparedStatementWrapper.java:788)

at org.hibernate.jdbc.AbstractBatcher.closePreparedStatement(AbstractBatcher.java:563)

at org.hibernate.jdbc.AbstractBatcher.closeStatement(AbstractBatcher.java:291)

at org.hibernate.id.insert.AbstractReturningDelegate.releaseStatement(AbstractReturningDelegate.java:82)

at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:60)

at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2327)

at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2834)

at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)

at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)

at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320)

at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)

at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)

at org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)

at org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)

at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)

at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:61)

at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:808)

at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:782)

at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:786)

at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:672)

at com.sun.enterprise.container.common.impl.EntityManagerWrapper.persist(EntityManagerWrapper.java:269)

at br.com.autsystem.dao.NFEletronicaDao.inserir(NFEletronicaDao.java:19)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:601)

at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)

at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)

at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5388)

at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)

at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)

at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)

at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)

at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:601)

at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)

at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)

at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:370)

at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5360)

at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5348)

at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)

… 44 more

Advertência: #{paisForm.gravar}: javax.ejb.EJBException

javax.faces.FacesException: #{paisForm.gravar}: javax.ejb.EJBException

at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)