I have enabled NSZombie's and I am getting the following message in my console when I am running my application:

 *** -[UIViewAnimationState release]: message sent to deallocated instance 0xf96d7e0

Here is the method that is performing the animation

-(void)loadAvatar:(STObject*)st
{   
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];    

    avatar.alpha = 0;
    avatar.frame = avatarRectSmall;

    avatar.image = [ImageCache getMemoryCachedImageAtUrl:st.avatar_url];

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:.50];

    avatar.frame = avatarRectNormal;
    [avatar setAlpha:1];
    [UIView commitAnimations];


    [pool release];
    pool = nil;
}

I don't always get a crash, only sometimes. I'm wondering what is getting released?