Adding PowerUps and trying to do ultimate collisions(but failed)

I've got copy of main with coin list on my PC, so if you dont want to
have all objects in one list to check collisions i can change it.
I don't know why this collision loop doesnt work. It crashes cause of
this:
for(iter = objects.begin(); iter != objects.end(); ++iter)
for(iter2 = iter; iter2 != objects.end(); ++iter2)