Xcode displays an error while building mac app for release

I am writing an application for OS X using core data. It's not a problem to build and run it for debugging, but when I switch to release or try to archive it, it throws an error

'/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSFetchRequestExpression.h:15:39: Attempting to use the forward class 'NSExpression' as superclass of 'NSFetchRequestExpression'

      

        
        
        
      

    

When I remove the whole fetch query from the code, it works fine. Does anyone know what the problem is? Thank.

Here's the title:

#import <Cocoa/Cocoa.h>
#import <CoreData/CoreData.h>
#import "EFMainController.h"

@interface EF_AppDelegate : NSObject
{
    IBOutlet NSMenu *statusMenu;
    NSStatusItem *statusItem;
    NSWindow *window;

    NSPersistentStoreCoordinator *persistentStoreCoordinator;
    NSManagedObjectModel *managedObjectModel;
    NSManagedObjectContext *managedObjectContext;
    EFMainController *mainController;
    NSTabView *tabView;
    IBOutlet NSImageView *dockTileView;
}

@property (nonatomic, retain) IBOutlet NSWindow *window;
@property (nonatomic, retain) IBOutlet EFMainController *mainController;
@property (assign) IBOutlet NSTabView *tabView;

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator;
- (NSManagedObjectModel *)managedObjectModel;
- (NSManagedObjectContext *)managedObjectContext;
- (IBAction)saveAction:sender;

@end

      

        
        
        
      

    

and

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@interface EFMainController : NSObject  {
    /* some variables */
}

/* some properties and actions */
@end

      

        
        
        
      

    

The stuff where I put comments has nothing to do with the main data