Try posting your tpl_header code - do you not have a logo?
A link to your site also
Here is code from one that works:
Code:
<!--bof-branding display-->
<div id="logoWrapper">
    <div id="logo"><?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">' . zen_image($template->get_template_dir(HEADER_LOGO_IMAGE, DIR_WS_TEMPLATE, $current_page_base,'images'). '/' . HEADER_LOGO_IMAGE, HEADER_ALT_TEXT) . '</a>'; ?></div>
		<div id="flashcontent">    
        <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0"        
        <param name="movie" value="header.swf">
        <param name="bgcolor" value="#FFFFFF">
        <param name="quality" value="high">
        <param name="wmode" value="transparent">
        <param name="allowscriptaccess" value="samedomain">

        <embed
          type="application/x-shockwave-flash"
          pluginspage="http://www.macromedia.com/go/getflashplayer"
          name="flashcontent"
          width="600" height="104"
          src="includes/templates/Template_dir/images/header.swf"
          bgcolor="#FFFFFF"
          quality="high"
          wmode="transparent"
          swliveconnect="true"
          allowscriptaccess="samedomain"
          <noembed>
          </noembed>
        </embed></object>
    </div>