Validates_acceptance_of problem

I’m having some difficulties getting validates_acceptance_of to work.
No matter whether I tick the checkbox for my terms and conditions on
my form, it will not submit it and shows my error message.

in my model i have:

validates_acceptance_of :agree_to_terms, :message => “”

in my view i have:

<%= error_message_on :user, :agree_to_terms, “You must agree to the
terms and conditions” %>
I agree to the terms and conditions
<%= f.check_box :agree_to_terms, ‘class’ => ‘smallinput’ %>

If anyone could shed some light on what i’m doing wrong it would be
greatly appreciated.
Thanks,
Paul.