Issue on hosted wiki

The folliwing error occurs when saving custom article documents; I can't seem to find the problem (probably something daft). Anyone ever seen this, or could suggest where to start looking?

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

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

]
        at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:321)
        at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:100)
        at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:94)
        at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:934)
        at com.xpn.xwiki.web.SaveAction.save(SaveAction.java:116)
        at com.xpn.xwiki.web.SaveAndContinueAction.action(SaveAndContinueAction.java:67)
        at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:149)
        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:710)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
        at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:118)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
        at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
        at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
        at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
        at java.lang.Thread.run(Thread.java:595)

Wrapped Exception:

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

]
        at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:1635)
        at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2208)
        at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2118)
        at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:2374)
        at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:84)
        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:141)
        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:1009)
        at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:356)
        at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
        at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:617)
        at com.xpn.xwiki.store.XWikiHibernateBaseStore.endTransaction(XWikiHibernateBaseStore.java:591)
        at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc(XWikiHibernateStore.java:316)
        at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:100)
        at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc(XWikiCacheStore.java:94)
        at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:934)
        at com.xpn.xwiki.web.SaveAction.save(SaveAction.java:116)
        at com.xpn.xwiki.web.SaveAndContinueAction.action(SaveAndContinueAction.java:67)
        at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:149)
        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:710)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
        at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:118)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
        at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
        at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
        at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
        at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
        at java.lang.Thread.run(Thread.java:595)