iPhone scrollView won't scroll after keyboard is closed

Question

I was trying to implement a way to have the UITextField move up when the keyboard opened so that the user could see what they were typing but after implementing the code - it locks my scroll. The view will scroll when the user first gets to that view but after inputting text and closing the keyboard it locks the view. I suspect that it is a problem somewhere in this code:

- (void) viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSLog(@"Registering for keyboard events");

// Register for the events
[[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector (keyboardDidShow:)
 name: UIKeyboardDidShowNotification
 object:nil];
[[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector (keyboardDidHide:)
 name: UIKeyboardDidHideNotification
 object:nil];

// Setup content size
scrollView.contentSize = CGSizeMake(SCROLLVIEW_CONTENT_WIDTH,
                                    SCROLLVIEW_CONTENT_HEIGHT);

//Initially the keyboard is hidden
keyboardVisible = NO;

}

-(void) viewWillDisappear:(BOOL)animated {
    NSLog (@"Unregister for keyboard events");
    [[NSNotificationCenter defaultCenter]
     removeObserver:self];
}

//**-------------------------------**
- (void) keyboardDidShow: (NSNotification *)notif {
    NSLog(@"Keyboard is visible");
    // If keyboard is visible, return
    if (keyboardVisible) {
        NSLog(@"Keyboard is already visible. Ignore notification.");
        return;
    }

    // Get the size of the keyboard.
    NSDictionary* info = [notif userInfo];
    NSValue* aValue = [info objectForKey:UIKeyboardBoundsUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;

    // Save the current location so we can restore
    // when keyboard is dismissed
    offset = scrollView.contentOffset;

    // Resize the scroll view to make room for the keyboard
    CGRect viewFrame = scrollView.frame;
    viewFrame.size.height -= keyboardSize.height;
    scrollView.frame = viewFrame;

    CGRect textFieldRect = [activeField frame];
    textFieldRect.origin.y += 10;
    [scrollView scrollRectToVisible:textFieldRect animated:YES];

    NSLog(@"ao fim");
    // Keyboard is now visible
    keyboardVisible = YES;
}

-(void) keyboardDidHide: (NSNotification *)notif {
    // Is the keyboard already shown
    if (!keyboardVisible) {
        NSLog(@"Keyboard is already hidden. Ignore notification.");
        return;
    }

    // Reset the frame scroll view to its original value
    scrollView.frame = CGRectMake(0, 0, SCROLLVIEW_CONTENT_WIDTH, SCROLLVIEW_CONTENT_HEIGHT);

    // Reset the scrollview to previous location
    scrollView.contentOffset = offset;

    // Keyboard is no longer visible
    keyboardVisible = NO;

}
-(BOOL) textFieldShouldBeginEditing:(UITextField*)textField {
    activeField = textField;
    return YES;
}

I defined the size above the #imports as:

#define SCROLLVIEW_CONTENT_HEIGHT 1000
#define SCROLLVIEW_CONTENT_WIDTH  320

Really not sure what the issue is.