Could not create a user [BonitaBPM 6.2.6 deploy with Jboss 5.1.0]

I a m using BonitaBPM 6.2.6 with Jboss 5.1.0. I logged for the first time in the portal with the technical user 'install' but I can't create another user. I get this error in the log. please help SEVERE [org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet] (http-127.0.0.1-8080-4) java.lang.NullPointerException at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:190) at org.bonitasoft.web.rest.server.api.organization.APIUser.checkPasswordRobustness(APIUser.java:89) at org.bonitasoft.web.rest.server.api.organization.APIUser.add(APIUser.java:81) at org.bonitasoft.web.rest.server.api.organization.APIUser.add(APIUser.java:54) at org.bonitasoft.web.rest.server.framework.API.runAdd(API.java:158) at org.bonitasoft.web.rest.server.framework.APIServletCall.doPost(APIServletCall.java:170) at org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.doPost(ToolkitHttpServlet.java:184) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.service(ToolkitHttpServlet.java:71) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.service(ToolkitHttpServlet.java:222) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.bonitasoft.console.common.server.login.filter.FilterManager.pageRedirect(FilterManager.java:88) at org.bonitasoft.console.common.server.login.filter.FilterManager.doFilter(FilterManager.java:68) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) at org.bonitasoft.console.security.SessionFixationValve.invoke(SessionFixationValve.java:77) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:744)