iOS Memory Warning & EXC_BAD_ACCESS

[sleaver]

When I stimulate a memory warning on a particular part of my app it goes into the didReceiveMemoryWarning method of the view controller behind the current one in the nav controller stack. However if I put a break point in a EXC_BAD_ACCESS error on this line:

[super didReceiveMemoryWarning];

I've used NSZombiesEnabled, however the app doesn't crash when I have it enabled. When it does crash I just get this in the stack trace:

0x01752a67 <+0027> mov (%edi),%esi

Any suggestions would be very much appreciated.