I have problem with login to JCR for modify node over POST request. Do you have any idea? thanks a lot.
I try to access over URL and the same error.

my code in esb file:

 part of form for modify currentNode property:

 <input type="hidden" name="currentNode@marshaler" value="EntireMarshaler"/>

 next:    var logger = document.getElementById("logger").value;

  var url = "config?time=" + new Date().getTime();
  var queryString = "logger=" + logger;

  xmlHttp = createXMLHttpRequest();
  xmlHttp.onreadystatechange = processSaveSettings;
  xmlHttp.open("POST", url, true, "admin", "admin");
  xmlHttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;");
  xmlHttp.send(queryString);


log file:

org.apache.sling.servlets.post.impl.operations.ModifyOperation Exception during response processing. javax.jcr.AccessDeniedException: /content/servicemix/config: not allowed to modify item
 at org.apache.jackrabbit.core.ItemImpl.validateTransientItems(ItemImpl.java:483)
 at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1205)
 at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:897)
 at org.apache.sling.jcr.base.internal.PooledSession.save(PooledSession.java:255)
 at org.apache.sling.servlets.post.AbstractSlingPostOperation.run(AbstractSlingPostOperation.java:82)
 at org.apache.sling.servlets.post.impl.SlingPostServlet.doPost(SlingPostServlet.java:142)
 at org.apache.sling.api.servlets.SlingAllMethodsServlet.mayService(SlingAllMethodsServlet.java:143)
 at org.apache.sling.api.servlets.SlingSafeMethodsServlet.service(SlingSafeMethodsServlet.java:338)
 at org.apache.sling.api.servlets.SlingSafeMethodsServlet.service(SlingSafeMethodsServlet.java:370)
 at org.apache.sling.engine.impl.request.RequestData.service(RequestData.java:462)
 at org.apache.sling.engine.impl.SlingMainServlet.processRequest(SlingMainServlet.java:419)
 at org.apache.sling.engine.impl.filter.RequestSlingFilterChain.render(RequestSlingFilterChain.java:48)
 at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:54)
 at org.apache.sling.engine.impl.debug.RequestProgressTrackerLogFilter.doFilter(RequestProgressTrackerLogFilter.java:59)
 at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter(AbstractSlingFilterChain.java:52)
 at org.apache.sling.engine.impl.SlingMainServlet.service(SlingMainServlet.java:273)
 at org.apache.sling.engine.impl.SlingMainServlet.service(SlingMainServlet.java:171)
 at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
 at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
 at org.ops4j.pax.web.service.internal.HttpServiceServletHandler.handle(HttpServiceServletHandler.java:51)
 at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
 at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:722)
 at org.ops4j.pax.web.service.internal.HttpServiceContext.handle(HttpServiceContext.java:87)
 at org.ops4j.pax.web.service.internal.JettyServerHandlerCollection.handle(JettyServerHandlerCollection.java:63)
 at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
 at org.mortbay.jetty.Server.handle(Server.java:324)
 at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
 at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:842)
 at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:648)
 at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
 at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
 at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
 at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:450)


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Best regards / S pozdravem
Vladislav Krejčiřík

http://www.vkrejcirik.info