JBPM删除流程实例时出错了

在系统忙时，删除JBPM流程实例时容易出错，错误如下：某位帮我解答一下，本人对hibernate不太了解
org.jbpm.persistence.JbpmPersistenceException: couldn't commit hibernate session
at org.jbpm.persistence.db.DbPersistenceService.close(DbPersistenceService.java:172)
at org.jbpm.svc.Services.close(Services.java:211)
at org.jbpm.JbpmContext.close(JbpmContext.java:139)
at org.jbpm.web.JbpmContextFilter.doFilter(JbpmContextFilter.java:85)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
Caused by: org.hibernate.StaleStateException: Unexpected row count: 0 expected: 1
at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:27)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2291)
at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2440)
at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:65)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:243)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:227)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:145)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:296)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:980)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:353)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
at org.jbpm.persistence.db.DbPersistenceService.close(DbPersistenceService.java:162)
... 27 more