title: -1 error message while trying to run H2O XGboost
body: <p>I am running H2O 3.10.5.3 (on  hadoop cdh5.8) on a remote server, connected to my local machine using R (3.4.1) with 'h2o.init(startH2O=F, port=54321)'.</p>
  
  <p>The code below works fine:</p>
  
  <pre><code>Train.hex &lt;- as.h2o(iris)
  h2o.gbm(x="Sepal.Length", y="Petal.Width", training_frame = Train.hex) 
  </code></pre>
  
  <p>but xgboost does not work and generates the following error message:</p>
  
  <pre><code>h2o.xgboost(x="Sepal.Length", y="Petal.Width", training_frame = Train.hex) 
  
  
  ERROR: Unexpected HTTP Status code: 500 Server Error (url = http://localhost:54321/3/ModelBuilders/xgboost)
  
  java.lang.ArrayIndexOutOfBoundsException
   [1] "java.lang.ArrayIndexOutOfBoundsException: -1"                                                                       
   [2] "    hex.ModelBuilder.make(ModelBuilder.java:117)"                                                                   
   [3] "    water.api.ModelBuildersHandler.fetch(ModelBuildersHandler.java:35)"                                             
   [4] "    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)"                                                    
   [5] "    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)"                                  
   [6] "    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)"                          
   [7] "    java.lang.reflect.Method.invoke(Method.java:498)"                                                               
   [8] "    water.api.Handler.handle(Handler.java:63)"                                                                      
   [9] "    water.api.RequestServer.serve(RequestServer.java:448)"                                                          
  [10] "    water.api.RequestServer.doGeneric(RequestServer.java:297)"                                                      
  [11] "    water.api.RequestServer.doGet(RequestServer.java:221)"                                                          
  [12] "    javax.servlet.http.HttpServlet.service(HttpServlet.java:707)"                                                   
  [13] "    javax.servlet.http.HttpServlet.service(HttpServlet.java:820)"                                                   
  [14] "    org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)"                                         
  [15] "    org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:503)"                                     
  [16] "    org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)"                             
  [17] "    org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:429)"                                      
  [18] "    org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)"                              
  [19] "    org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)"                                  
  [20] "    org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)"                          
  [21] "    org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)"                                
  [22] "    water.JettyHTTPD$LoginHandler.handle(JettyHTTPD.java:183)"                                                      
  [23] "    org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)"                          
  [24] "    org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)"                                
  [25] "    org.eclipse.jetty.server.Server.handle(Server.java:366)"                                                        
  [26] "    org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)"                 
  [27] "    org.eclipse.jetty.server.BlockingHttpConnection.handleRequest(BlockingHttpConnection.java:53)"                  
  [28] "    org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:971)"                
  [29] "    org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1033)"
  [30] "    org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)"                                               
  [31] "    org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)"                                          
  [32] "    org.eclipse.jetty.server.BlockingHttpConnection.handle(BlockingHttpConnection.java:72)"                         
  [33] "    org.eclipse.jetty.server.bio.SocketConnector$ConnectorEndPoint.run(SocketConnector.java:264)"                   
  [34] "    org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)"                               
  [35] "    org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)"                                
  [36] "    java.lang.Thread.run(Thread.java:745)"                                                                          
  
  Error in .h2o.doSafeREST(h2oRestApiVersion = h2oRestApiVersion, urlSuffix = page,  : 
  
  
  ERROR MESSAGE:
  
  -1
  </code></pre>
  
  <p>Can anyone help me to understand what is going on?</p>
  
  <p>Many thanks in advance,
  Kere</p>