Autocomplete error please help

Hi, I need to implement auto complete in my form. I have installed autocaomplete for rails 2.0 in the

person form i have <%form_for(:person,:url=>{:action =>"submit_tag"} do p %> First Name:<%= text_field_with_auto_complete p, "first_name" %> .... <%end%>

in the person controller i have

auto_complete_for :person, :first_name

also in the application layout i have <%= javascript_include_tag :defaults %>

Now when i try to open the page the autocomplete does not work and i get the following:

line: 667 char: 1 Error : Object expected code: 0

Please tell me what is going wrong Thank you.