1. the route is not quite right
2. the form is posting to an address not quite right
3. you're running rails in production and the process hasn't been restarted

getting other eyes on the code you have for 1 and 2 would probably help you. maybe a link to the contact form?

<form action="/contact_submit" method="post" accept-charset="utf-8">
   <label>Name *</label>
      <input type="text" id="f_contact_name" name="contact[name]" />
   <label>Email Address *</label>
      <input type="text" id="f_contact_email" name="contact[email]" />
   <label>Message *</label>
      <textarea name="contact[comment]" id="f_contact_comment"></textarea>
   <input type="submit" name="submit" id="submit" value="Submit" />
</form>