diff --git a/mozilla/extensions/irc/locales/en-US/chrome/chatzilla.properties b/mozilla/extensions/irc/locales/en-US/chrome/chatzilla.properties
index 1a479e8ca7e..0e884524bb1 100644
--- a/mozilla/extensions/irc/locales/en-US/chrome/chatzilla.properties
+++ b/mozilla/extensions/irc/locales/en-US/chrome/chatzilla.properties
@@ -806,6 +806,9 @@ msg.need.oper.password = Please enter a password for obtaining IRC Operator priv
 
 # Better IRC error messages
 msg.irc.381 = You are now an IRC Operator.
+msg.irc.401 = The nickname ``$S'' does not exist.
+msg.irc.402 = The server ``$S'' does not exist.
+msg.irc.403 = The channel ``$S'' does not exist.
 msg.irc.464 = Incorrect password, please try again with the correct password.
 msg.irc.464.login = Please specify your password using the "/pass" command to continue connecting.
 msg.irc.471 = This channel has reached its set capacity; you cannot join it.
diff --git a/mozilla/extensions/irc/xul/content/handlers.js b/mozilla/extensions/irc/xul/content/handlers.js
index 9592578075a..0d139806526 100644
--- a/mozilla/extensions/irc/xul/content/handlers.js
+++ b/mozilla/extensions/irc/xul/content/handlers.js
@@ -1592,32 +1592,39 @@ function my_listrply (e)
     }
 }
 
-CIRCNetwork.prototype.on401 =
-function my_401 (e)
+CIRCNetwork.prototype.on401 = /* ERR_NOSUCHNICK */
+CIRCNetwork.prototype.on402 = /* ERR_NOSUCHSERVER */
+CIRCNetwork.prototype.on403 = /* ERR_NOSUCHCHANNEL */
+function my_401(e)
 {
-    var target = e.server.toLowerCase(e.params[2]);
-    if (target in this.users && "messages" in this.users[target])
-    {
-        this.users[target].displayHere(e.params[3]);
-    }
-    else if (target in this.primServ.channels &&
-             "messages" in this.primServ.channels[target])
-    {
-        this.primServ.channels[target].displayHere(e.params[3]);
-    }
+    var server, channel, user;
+
+    /* Note that servers generally only send 401 and 402, sharing the former
+     * between nicknames and channels, but we're ready for anything.
+     */
+    if (e.code == 402)
+        server = e.decodeParam(2);
+    else if (arrayIndexOf(e.server.channelTypes, e.params[2][0]) != -1)
+        channel = new CIRCChannel(e.server, null, e.params[2]);
     else
+        user = new CIRCUser(e.server, null, e.params[2]);
+
+    if (user && this.whoisList && (user.canonicalName in this.whoisList))
     {
-        if (this.whoisList && (target in this.whoisList))
-        {
-            // if this is from a whois, send a whowas and don't display anything
-            this.primServ.whowas(target, 1);
-            this.whoisList[target] = false;
-        }
-        else
-        {
-            display(toUnicode(e.params[3], this));
-        }
+        // If this is from a /whois, send a /whowas and don't display anything.
+        this.primServ.whowas(user.unicodeName, 1);
+        this.whoisList[user.canonicalName] = false;
+        return;
     }
+
+    if (user)
+        user.display(getMsg(MSG_IRC_401, [user.unicodeName]), e.code);
+    else if (server)
+        this.display(getMsg(MSG_IRC_402, [server]), e.code);
+    else if (channel)
+        channel.display(getMsg(MSG_IRC_403, [channel.unicodeName]), e.code);
+    else
+        dd("on401: unreachable code.");
 }
 
 /* 464; "invalid or missing password", occurs as a reply to both OPER and
diff --git a/mozilla/extensions/irc/xul/content/static.js b/mozilla/extensions/irc/xul/content/static.js
index edaff25e8c7..4bf279f4b7a 100644
--- a/mozilla/extensions/irc/xul/content/static.js
+++ b/mozilla/extensions/irc/xul/content/static.js
@@ -4004,28 +4004,53 @@ function my_splitlinesforsending(line)
     return realLines;
 }
 
+/* Displays a network-centric message on the most appropriate view.
+ *
+ * When |client.SLOPPY_NETWORKS| is |true|, messages will be displayed on the
+ * *current* view instead of the network view, if the current view is part of
+ * the same network.
+ */
 CIRCNetwork.prototype.display =
-function net_display (message, msgtype, sourceObj, destObj)
+function net_display(message, msgtype, sourceObj, destObj)
 {
     var o = getObjectDetails(client.currentObject);
-
     if (client.SLOPPY_NETWORKS && client.currentObject != this &&
         o.network == this && o.server && o.server.isConnected)
     {
-        client.currentObject.display (message, msgtype, sourceObj, destObj);
+        client.currentObject.display(message, msgtype, sourceObj, destObj);
     }
     else
     {
-        this.displayHere (message, msgtype, sourceObj, destObj);
+        this.displayHere(message, msgtype, sourceObj, destObj);
     }
 }
 
+/* Displays a channel-centric message on the most appropriate view.
+ *
+ * If the channel view already exists (visible or hidden), messages are added
+ * to it; otherwise, messages go to the *network* view.
+ */
+CIRCChannel.prototype.display =
+function chan_display(message, msgtype, sourceObj, destObj)
+{
+    if ("messages" in this)
+        this.displayHere(message, msgtype, sourceObj, destObj);
+    else
+        this.parent.parent.displayHere(message, msgtype, sourceObj, destObj);
+}
+
+/* Displays a user-centric message on the most appropriate view.
+ *
+ * If the user view already exists (visible or hidden), messages are added to
+ * it; otherwise, it goes to the *current* view if the current view is part of
+ * the same network, or the *network* view if not.
+ */
 CIRCUser.prototype.display =
 function usr_display(message, msgtype, sourceObj, destObj)
 {
     if ("messages" in this)
     {
-        this.displayHere (message, msgtype, sourceObj, destObj);
+        this.displayHere(message, msgtype, sourceObj, destObj);
     }
     else
     {
@@ -4033,19 +4058,22 @@ function usr_display(message, msgtype, sourceObj, destObj)
         if (o.server && o.server.isConnected &&
             o.network == this.parent.parent &&
             client.currentObject.TYPE != "IRCUser")
-            client.currentObject.display (message, msgtype, sourceObj, destObj);
+            client.currentObject.display(message, msgtype, sourceObj, destObj);
         else
-            this.parent.parent.displayHere (message, msgtype, sourceObj,
-                                            destObj);
+            this.parent.parent.displayHere(message, msgtype, sourceObj,
+                                           destObj);
     }
 }
 
+/* Displays a DCC user/file transfer-centric message on the most appropriate view.
+ *
+ * If the DCC user/file transfer view already exists (visible or hidden),
+ * messages are added to it; otherwise, messages go to the *current* view.
+ */
 CIRCDCCChat.prototype.display =
 CIRCDCCFileTransfer.prototype.display =
 function dcc_display(message, msgtype, sourceObj, destObj)
 {
-    var o = getObjectDetails(client.currentObject);
-
     if ("messages" in this)
         this.displayHere(message, msgtype, sourceObj, destObj);
     else
@@ -4110,7 +4138,6 @@ function this_getFontCSS(format)
 client.display =
 client.displayHere =
 CIRCNetwork.prototype.displayHere =
-CIRCChannel.prototype.display =
 CIRCChannel.prototype.displayHere =
 CIRCUser.prototype.displayHere =
 CIRCDCCChat.prototype.displayHere =