Ajax response is always 0

I am trying to figure out why my Ajax response is always 0. I am trying to load in meta data into a Jquery UI Dialog box based on the ID of the link clicked. All of this is in a single.php template file – not sure if that is the cause or not.

Here is my code(edited for space):

            jQuery( '#meta-dialog-box' ).dialog({
            width: "500px",
            autoOpen: false,
            show: "blind",
            hide: "explode",
            resizeable: false,
            draggable: false,
            modal: true,
            position: "center",
            closeText: "X",
            dialogClass: "co-meta-dialog-wrapper"
        });

        jQuery('a.co-meta-dialog').click(function(){
            var id = $(this).attr('id');
            var taxonomy = id.replace("co-","");
            taxonomy = taxonomy.replace("-dialog","");
            var title = $(this).text();
            jQuery( "#meta-dialog-box" ).dialog( "option", "title", title );
            jQuery( "#meta-dialog-box" ).dialog( "open" );
            jQuery( "#meta-dialog-box" ).html( '<img width="62px" height="62px" style="margin:0 auto;" src="<?php bloginfo('template_directory');?>/images/loading.gif" alt="loading..." />' );             

            //$( "#meta-dialog-box" ).html('Meta Dialog Box For: ' + id);

            switch( id ){
                case 'co-location-dialog':
                    dialog_action = 'show_co_location_dialog';
                break;

                case 'co-contact-dialog':
                    dialog_action = 'show_co_contact_dialog';
                break;

                //and so on....

                default:
                break;
            }//end switch

            jQuery.post(            
                UiAjax.ajaxurl,
                {
                    action : dialog_action,
                    postid: '<?php echo $postid; ?>',
                    tax: taxonomy
                },          
                function( response, data, status ) {
                    jQuery('#meta-dialog-box').html(response);
                    //alert(data + ' ' + status);
                }
            );
            return false;           
        });

I have check Firebug and my action is getting through correctly. So it seems my PHP call back is not being fired correctly. All my call back PHP functions have die(); at the end of them. And are set to print the meta data. I tried echo and return but still no luck.

I have all my ajax actions in my functions.php file like so:

//location|address
add_action('wp_ajax_show_co_location_dialog', array('DS_Lingerie','get_dialog_address') );
//contact info 
add_action('wp_ajax_show_co_contact_dialog', array('DS_Lingerie','get_dialog_contact_info') );

Do I need to set up a plugin to do this? Or am I missing something else entirely? I have been banging my head against the wall for about 6 hours now and cannot figure out what I am doing wrong here.

Any and all help is greatly appreciated! I may need to rethink how I have this set up, perhaps use a different modal/dialog function or something like that. Suggestions and insights are 100% welcome! Thanks in advance.