diff --git a/bitbake/lib/bb/server/xmlrpc.py b/bitbake/lib/bb/server/xmlrpc.py
index b7647c198f..17eb28b7d4 100644
--- a/bitbake/lib/bb/server/xmlrpc.py
+++ b/bitbake/lib/bb/server/xmlrpc.py
@@ -97,10 +97,10 @@ class BitBakeServerCommands():
 
         # we don't allow connections if the cooker is running
         if (self.cooker.state in [bb.cooker.state.parsing, bb.cooker.state.running]):
-            return None
+            return None, "Cooker is busy: %s" % bb.cooker.state.get_name(self.cooker.state)
 
         self.event_handle = bb.event.register_UIHhandler(s, True)
-        return self.event_handle
+        return self.event_handle, 'OK'
 
     def unregisterEventHandler(self, handlerNum):
         """
diff --git a/bitbake/lib/bb/ui/uievent.py b/bitbake/lib/bb/ui/uievent.py
index 7fc50c759a..80686a65be 100644
--- a/bitbake/lib/bb/ui/uievent.py
+++ b/bitbake/lib/bb/ui/uievent.py
@@ -52,19 +52,21 @@ class BBUIEventQueue:
         # giving up
 
         while self.EventHandler == None and count_tries < 5:
-            self.EventHandle = self.BBServer.registerEventHandler(self.host, self.port)
+            self.EventHandle, error = self.BBServer.registerEventHandler(self.host, self.port)
 
             if (self.EventHandle != None):
                 break
 
-            bb.warn("Could not register UI event handler %s:%d, retry" % (self.host, self.port))
+            errmsg = "Could not register UI event handler. Error: %s, " \
+                     "host %s, port %d" % (error, self.host, self.port)
+            bb.warn("%s, retry" % errmsg)
             count_tries += 1
             import time
             time.sleep(1)
 
 
         if self.EventHandle == None:
-            raise Exception("Could not register UI event handler")
+            raise Exception(errmsg)
 
         self.server = server