diff --git a/include/util.js b/include/util.js
index c145d5a6cfcdb16940df472dbdb8b21b2a469454..a6045dacf1e19f058ac93ec10afa390987a405ae 100644
--- a/include/util.js
+++ b/include/util.js
@@ -341,6 +341,10 @@ Util.set_defaults = function (obj, conf, defaults) {
 
     for (i = 0; i < keys.length; i++) {
         var setter = obj['_raw_set_' + keys[i]];
+        if (!setter) {
+          Util.Warn('Invalid property ' + keys[i]);
+          continue;
+        }
 
         if (conf[keys[i]]) {
             setter.call(obj, conf[keys[i]]);
diff --git a/tests/vnc_perf.html b/tests/vnc_perf.html
index 18aba3557a33dcd298657bf6321a56d1630033e5..c439e95545a1d88c113f3a24005c931bae3df8fd 100644
--- a/tests/vnc_perf.html
+++ b/tests/vnc_perf.html
@@ -202,7 +202,7 @@
                 dbgmsg("  " + enc + ": " + VNC_frame_data_multi[enc].length);
             }
             rfb = new RFB({'target': $D('VNC_canvas'),
-                           'updateState': updateState});
+                           'onUpdateState': updateState});
             rfb.testMode(send_array, VNC_frame_encoding);
         }
     </script>
diff --git a/tests/vnc_playback.html b/tests/vnc_playback.html
index 9d7f31f59c8b0144137565f5eaffbaf63c453acc..b5faf93cce9c186cfb1c3a22201b84ec2d3cad2c 100644
--- a/tests/vnc_playback.html
+++ b/tests/vnc_playback.html
@@ -131,7 +131,7 @@
             if (fname) {
                 message("VNC_frame_data.length: " + VNC_frame_data.length);
                 rfb = new RFB({'target': $D('VNC_canvas'),
-                               'updateState': updateState});
+                               'onUpdateState': updateState});
             }
         }
     </script>
diff --git a/vnc_auto.html b/vnc_auto.html
index 53b8220cfbd10071c8123b7c9c981af88bd5c655..ff376fec166a18299b9bbd7a4e97392618ff5370 100644
--- a/vnc_auto.html
+++ b/vnc_auto.html
@@ -198,7 +198,7 @@
                            'local_cursor': WebUtil.getQueryVar('cursor', true),
                            'shared':       WebUtil.getQueryVar('shared', true),
                            'view_only':    WebUtil.getQueryVar('view_only', false),
-                           'updateState':  updateState,
+                           'onUpdateState':  updateState,
                            'onXvpInit':    xvpInit,
                            'onPasswordRequired':  passwordRequired});
             rfb.connect(host, port, password, path);