Terminating App - NSInvalidArgumentException

Crashing when running Parse Anypic code.

-(void)sendCommentButton:(id) sender {
        NSString *trimmedComment = [commentTextView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
        if (trimmedComment.length != 0 && [self.photo objectForKey:kPAPPhotoUserKey]) {
            PFObject *comment = [PFObject objectWithClassName:kPAPActivityClassKey];
            [comment setObject:trimmedComment forKey:kPAPActivityContentKey]; // Set comment text
            [comment setObject:[self.photo objectForKey:kPAPPhotoUserKey] forKey:kPAPActivityToUserKey]; // Set toUser
            [comment setObject:[PFUser currentUser] forKey:kPAPActivityFromUserKey]; // Set fromUser
            [comment setObject:kPAPActivityTypeComment forKey:kPAPActivityTypeKey];
            [comment setObject:self.photo forKey:kPAPActivityPhotoKey];
            [comment setObject:self.photoFile forKey:@"attachmentFile"];


            PFACL *ACL = [PFACL ACLWithUser:[PFUser currentUser]];
            [ACL setPublicReadAccess:YES];
            [ACL setWriteAccess:YES forUser:[self.photo objectForKey:kPAPPhotoUserKey]];
            comment.ACL = ACL;

            [[PAPCache sharedCache] incrementCommentCountForPhoto:self.photo];

            // Show HUD view
            [MBProgressHUD showHUDAddedTo:self.view.superview animated:YES];

            // If more than 5 seconds pass since we post a comment, stop waiting for the server to respond
            NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:5.0f target:self selector:@selector(handleCommentTimeout:) userInfo:@{@"comment": comment} repeats:NO];

            [comment saveEventually:^(BOOL succeeded, NSError *error) {
                [timer invalidate];

                if (error && error.code == kPFErrorObjectNotFound) {
                    [[PAPCache sharedCache] decrementCommentCountForPhoto:self.photo];
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Could not post comment", nil) message:NSLocalizedString(@"This photo is no longer available", nil) delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
                    [alert show];
                    [self.navigationController popViewControllerAnimated:YES];
                }

                [[NSNotificationCenter defaultCenter] postNotificationName:PAPPhotoDetailsViewControllerUserCommentedOnPhotoNotification object:self.photo userInfo:@{@"comments": @(self.objects.count + 1)}];

                [MBProgressHUD hideHUDForView:self.view.superview animated:YES];
                [self loadObjects];
            }];

        }

        [self.commentTextView setText:@""];
        [self.commentTextView resignFirstResponder];
        if (self.photoFile != nil) {
            self.photoFile = nil;
        }


}

Picking an Image

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    NSLog(@"Hello");
    UIImage *img = [info objectForKey:UIImagePickerControllerOriginalImage];


    // JPEG to decrease file size and enable faster uploads & downloads
    NSData *imageData = UIImageJPEGRepresentation(img, 0.8f);

    self.photoFile = [PFFile fileWithData:imageData];

    // Request a background execution task to allow us to finish uploading the photo even if the app is backgrounded
    self.fileUploadBackgroundTaskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
        [[UIApplication sharedApplication] endBackgroundTask:self.fileUploadBackgroundTaskId];
    }];

    NSLog(@"Requested background expiration task with id %lu for Anypic photo upload", (unsigned long)self.fileUploadBackgroundTaskId);
    [self.photoFile saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
        if (succeeded) {
            NSLog(@"Photo uploaded successfully");
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Photo Uploaded"
                                                            message:@"successfully"
                                                           delegate:self
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
            [alert show];
        } else {

            [[UIApplication sharedApplication] endBackgroundTask:self.fileUploadBackgroundTaskId];

        }
    }];

    [self dismissViewControllerAnimated:YES completion:nil];
}

Question: Why is it crashing? I believe this is the code that is crashing it. What I did to crash it was not add an attachmentFile and just put a comment.

If you need more code or need any clarifications please comment down below