Error "ActionController::InvalidAuthenticityToken"

Hi,
I am using rails 2.2
I an getting this error.
“ActionController::InvalidAuthenticityToken”

I have an code in my erb file is like this:

<div id="pdf_title" style="display:none">
  Title: <%=text_field(:page, :title, :size => 20)%>
  <a href="#" onclick="add_title();">Create</a>
</div>

Whenever I am clicking onto the Create link I am getting error.
“ActionController::InvalidAuthenticityToken”
Could any one please help me out urgently.
I am new in rails 2.0 and above
Thanks,
Tushar