Index: UI/MailerUI/UIxMailFolderActions.m
--- UI/MailerUI/UIxMailFolderActions.m.orig
+++ UI/MailerUI/UIxMailFolderActions.m
@@ -149,7 +149,7 @@
 
   if (!newFolderName || [newFolderName length] == 0)
     {
-      message = [NSDictionary dictionaryWithObject: [self labelForKey: @"Missing name parameter" inContext: context]
+      message = [NSMutableDictionary dictionaryWithObject: [self labelForKey: @"Missing name parameter" inContext: context]
                                             forKey: @"message"];
       response = [self responseWithStatus: 500 andJSONRepresentation: message];
     }
@@ -159,7 +159,7 @@
       error = [co renameTo: newFolderName];
       if (error)
         {
-          message = [NSDictionary dictionaryWithObject: [self labelForKey: @"Unable to rename folder." inContext: context]
+          message = [NSMutableDictionary dictionaryWithObject: [self labelForKey: @"Unable to rename folder." inContext: context]
                                                 forKey: @"message"];
           response = [self responseWithStatus: 500 andJSONRepresentation: message];
         }
@@ -184,7 +184,7 @@
           else
             sievePath = newFolderPath;
 
-          message = [NSDictionary dictionaryWithObjectsAndKeys:
+          message = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                     newFolderPath, @"path", sievePath, @"sievePath", nil];
           response = [self responseWithStatus: 200 andJSONRepresentation: message];
         }
@@ -232,7 +232,7 @@
 
   if (!newParentPath || [newParentPath length] == 0)
     {
-      message = [NSDictionary dictionaryWithObject: [self labelForKey: @"Missing parent parameter" inContext: context]
+      message = [NSMutableDictionary dictionaryWithObject: [self labelForKey: @"Missing parent parameter" inContext: context]
                                             forKey: @"message"];
       response = [self responseWithStatus: 500 andJSONRepresentation: message];
     }
@@ -244,7 +244,7 @@
       error = [co renameTo: newFolderPath];
       if (error)
         {
-          message = [NSDictionary dictionaryWithObject: [self labelForKey: @"Unable to move folder." inContext: context]
+          message = [NSMutableDictionary dictionaryWithObject: [self labelForKey: @"Unable to move folder." inContext: context]
                                                 forKey: @"message"];
           response = [self responseWithStatus: 500 andJSONRepresentation: message];
         }
@@ -287,7 +287,7 @@
           else
             sievePath = newFolderPath;
 
-          message = [NSDictionary dictionaryWithObjectsAndKeys:
+          message = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                     newFolderPath, @"path", sievePath, @"sievePath", nil];
           response = [self responseWithStatus: 200 andJSONRepresentation: message];
         }
@@ -541,7 +541,7 @@
     }
   else
     {
-      data = [NSDictionary dictionaryWithObject: [self labelForKey: @"Missing 'uids' parameter." inContext: context]
+      data = [NSMutableDictionary dictionaryWithObject: [self labelForKey: @"Missing 'uids' parameter." inContext: context]
                                          forKey: @"message"];
       response = [self responseWithStatus: 500 andJSONRepresentation: data];
     }
