How about the relative url? Make it a full url to the file in the embed tag. The reason it works in your header link the file one cause the file exists there. 468x60.swf does not exist in the photopost directory
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,0,0" width="468" height="60" id="468x60" align="middle">
<param name="allowScriptAccess" value="sameDomain" />
<param name="movie" value="468x60.swf" />
<param name="quality" value="high" />
<param name="bgcolor" value="#ffffff" />
<embed src="468x60.swf" quality="high" bgcolor="#ffffff" width="468" height="60" name="468x60" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" />
</object>