记忆管理:我在这里做错什么了吗?

在我的iphone应用程序中,有极少数情况下,在下面的代码中的for循环之后,我会崩溃:

ABAddressBookRef addressBookInit = ABAddressBookCreate();

CFMutableArrayRef abContacts =
(CFMutableArrayRef)ABAddressBookCopyArrayOfAllPeople(addressBookInit); // get array of all contacts
CFArraySortValues (abContacts, CFRangeMake(0, CFArrayGetCount(abContacts)), (CFComparatorFunction)ABPersonComparePeopleByName, (void *)ABPersonGetSortOrdering());

NSArray *copypeople = (NSArray *) abContacts;
NSMutableArray *tempTheadlist = [[NSMutableArray alloc] init];

for (int i=0; i < copypeople.count; i++)
{
   NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
   ABRecordRef record = [copypeople objectAtIndex:i];
   if (blah blah)
         [tempThreadList addObject: someObject];
   [pool release];
}

// POINT OF CRASH AFTER LOOP ENDS

if (tempTheadlist.count > 0)
        [NSThread detachNewThreadSelector: @selector(loading_pictures:) toTarget:self withObject:tempTheadlist];


[tempTheadlist release];
[copypeople release];
CFRelease(addressBookInit);

有什么理由让它在这里崩溃?