Error message when changing sort order in object editor

http://www.curriki.org/xwiki/bin/view/Coll_LWL/Algebra1

I was reviewing one of our partner collections when I noticed a number of TRODs. I went into the Object Editor to check it out, and saw that many of the assets in the collection were ordered wrong. I re-ordered them (starting with 0-the last one). When I clicked save, I got this error message (below). I then viewed the collection I was working on, and it appeared that my changes were accepted.

Error number 3201 in 3: Exception while saving document Coll_LWL.Algebra1
Wrapped Exception: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.xpn.xwiki.objects.LargeStringProperty#

XWiki.XWikiAdminGroup,
]
com.xpn.xwiki.XWikiException: Error number 3201 in 3: Exception while saving document Coll_LWL.Algebra1
Wrapped Exception: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.xpn.xwiki.objects.LargeStringProperty#

XWiki.XWikiAdminGroup,
]
at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:457)
at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97)
at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91)
at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1083)
at com.xpn.xwiki.web.SaveAction.save(SaveAction.java:120)
at com.xpn.xwiki.web.SaveAction.action(SaveAction.java:129)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:197)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:397)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:216)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:276)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:179)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:73)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:182)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at com.sun.enterprise.web.VirtualServerPipeline.invoke(VirtualServerPipeline.java:120)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:137)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:239)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.invokeAdapter(ProcessorTask.java:667)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.processNonBlocked(ProcessorTask.java:574)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:844)
at com.sun.enterprise.web.connector.grizzly.ReadTask.executeProcessorTask(ReadTask.java:287)
at com.sun.enterprise.web.connector.grizzly.ReadTask.doTask(ReadTask.java:212)
at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:252)
at com.sun.enterprise.web.connector.grizzly.WorkerThread.run(WorkerThread.java:75)

Wrapped Exception:

org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.xpn.xwiki.objects.LargeStringProperty#

XWiki.XWikiAdminGroup,
]
at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1765)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2407)
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2307)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2607)
at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:92)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:250)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:234)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:142)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:783)
at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:754)
at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:447)
at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:97)
at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:91)
at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:1083)
at com.xpn.xwiki.web.SaveAction.save(SaveAction.java:120)
at com.xpn.xwiki.web.SaveAction.action(SaveAction.java:129)
at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:197)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:397)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184)
at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:216)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:184)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:276)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:179)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:73)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:182)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at com.sun.enterprise.web.VirtualServerPipeline.invoke(VirtualServerPipeline.java:120)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:137)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:566)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:536)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:939)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:239)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.invokeAdapter(ProcessorTask.java:667)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.processNonBlocked(ProcessorTask.java:574)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:844)
at com.sun.enterprise.web.connector.grizzly.ReadTask.executeProcessorTask(ReadTask.java:287)
at com.sun.enterprise.web.connector.grizzly.ReadTask.doTask(ReadTask.java:212)
at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:252)
at com.sun.enterprise.web.connector.grizzly.WorkerThread.run(WorkerThread.java:75)