unable to edit an item in dspace6 jspui

[Compte Messagerie]

hello every body,

i have dspace 6.2 with jspui  on debian 9.1 , with : tomcat8, java8, maven3.5, ant1.10

whene i try to modify one item it indicates :

Internal System Error
The system has experienced an internal error. Please try to do what you were doing again, and if the problem persists, please contact us so we can fix the problem.

and that is what says dspace.log file :

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2021-04-12 10:49:34,399 INFO  org.dspace.app.webui.servlet.HandleServlet @ informat...@gmail.com:session_id=E24EBEC10834299F3A3B874D96172F5C:ip_addr=172.20.17.135:view_item:handle=123456789/734
2021-04-12 10:49:35,322 WARN  org.dspace.app.webui.servlet.DSpaceServlet @ informat...@gmail.com:session_id=E24EBEC10834299F3A3B874D96172F5C:ip_addr=172.20.17.135:general_jspui_error:java.lang.ArrayIndexOutOfBoundsException\colon; 0
java.lang.ArrayIndexOutOfBoundsException: 0
    at java.util.Arrays$ArrayList.get(Arrays.java:3841)
    at org.dspace.app.webui.servlet.HandleServlet.displayItem(HandleServlet.java:409)
    at org.dspace.app.webui.servlet.HandleServlet.doDSGet(HandleServlet.java:268)
    at org.dspace.app.webui.servlet.DSpaceServlet.processRequest(DSpaceServlet.java:126)
    at org.dspace.app.webui.servlet.DSpaceServlet.doGet(DSpaceServlet.java:73)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.dspace.rdf.negotiation.NegotiationFilter.doFilter(NegotiationFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.dspace.utils.servlet.DSpaceWebappServletFilter.doFilter(DSpaceWebappServletFilter.java:78)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

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all other items, communities and collections are normaly editable .

what can i do to correct this problem ?

thank you.