Halloween 2013 update glitch- can't see gremlins

[xirtam82]

Since the start of the Halloween update I have been unable to see the gremlins that have been put in my town thus not able to collect goo When my friends try to add gremlins they are told my town is overrun Can you please assist as I am unable to reach goo goals without this Please help

It appears other have had this problem too please help