Like MeowChow's, 17 characters, but this one can be run more than once without error: 
sub all_ne {
map{$_ ne$_[0]}@_
}

[download]
Update:
Upon reading the entire thread, this does seem similar to what tilly posted. Strange. This means that I can now say: 
sub all_ne {
map$_[0]ne$_,@_
}

[download]
Which is incredibly only 15 characters. Thanks to tilly for the obvious parameter re-ordering trick. I had been mashing around with grep during testing, but discarded it as too bulky.

Update-2:
For whatever reason, it seems I've implemented the function in the negative sense.

In reply to Re: (Golf) All Elements of an Array Equal by tadman
in thread Golf Challenge: all elements of an array equal by princepawn

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