I'm not sure that this will be any help to anyone, but I was testing the 'banning' feature in my gallery, and once i logged into the banned account it banned my IP address, and wouldn't let me logout! To solve this quickly, I went into phpMyAdmin, and found the table in coppermine called (i think) banning, and found my username, and deleted it!
Thanks-I just feel good to have accomplished something:)
right now, the admin can ban himself - consider this a bug, if you want. May be fixed in a future version. Right now, the admin has to take care he doesn't ban himself...
GauGau