Change Post Action URL

I am trying to get Gravity Forms to work on a subdomain but the post action URL points to a relative path so it will not submit. Where can I make it a full URL?

Page Example:
http://search.traditionalsellers.com/idx/13657/details.php?listingID=4073699&idxID=063

<form method='post' enctype='multipart/form-data' target='gform_ajax_frame_1' id='gform_1' action='/#gf_1'> needs to be <form method='post' enctype='multipart/form-data' target='gform_ajax_frame_1' id='gform_1' action='http://www.traditionalsellers.com/#gf_1'>

I don't think the problem is a scripting issue. Because I am trying to use the form on the search.traditionalsellers.com subdomain, I need to rewrite the form action URL to the main domain. I got close by editing lines starting at 440 in form_display.php to the following:

if($use_anchor !== false){
$form_string .="";
$action .= "http://www.traditionalsellers.com/#gf_$form_id";
}
$target = $ajax ? "target='http://www.traditionalsellers.com/gform_ajax_frame_{$form_id}'" : "";

The problem is that the the action part of the form adds in an extra "/" right at the beginning:

action='/http://www.traditionalsellers.com/#gf_1'

Does perhaps the gform_form_tag filter help with your problem?