I had the same problem - and more or less by coincidence got it working

1. monoslideshow.xml and .swf are in the same folder (
http://www.inselhaus-foehr.de/media/flash)
2. content of monoslideshow.xml:
<album thumbnail="
http://www.inselhaus-foehr.de/media/flash/images/Bild1.JPG"
itemPath="
http://www.inselhaus-foehr.de/media/flash/images"
thumbnailPath="
http://www.inselhaus-foehr.de/media/flash/thumbs">
<configuration>
<transition kenBurnsMode="randomZoomIn" />
</configuration>
<contents>
<image source="Bild1.JPG" title="" description="" />
<image source="Bild2.JPG" title="" description="" />
<image source="Bild3.JPG" title="" description="" />
<image source="Bild4.JPG" title="" description="" />
<image source="Bild5.JPG" title="" description="" />
<image source="Bild6.JPG" title="" description="" />
<image source="Bild7.JPG" title="" description="" />
<image source="Bild8.JPG" title="" description="" />
<image source="Bild9.JPG" title="" description="" />
<image source="Bild10.JPG" title="" description="" />
<image source="Bild11.JPG" title="" description="" />
<image source="Bild12.JPG" title="" description="" />
<image source="Bild13.JPG" title="" description="" />
</contents>
</album>
3. swfobjects.js is not on my server. WB utomatically uses an AJAX-Script....
4. source-code of my php-side:
<div id="content">
<h2>Impressionen</h2>
<p><a class="section_anchor" id="wb_43" name="wb_43"></a><p>
<script src="
http://ajax.googleapis.com/ajax/libs/swfobject/2.2/swfobject.js" type="text/javascript">//swfobject plugin</script>
<script type="text/javascript">
/*<![CDATA[*/
/* FCK swfobject v1.5 */
document.write('<div id="flash2011516225758" style="width:600px; height:300px;"><a href="
http://www.macromedia.com/go/getflashplayer">Get the Flash Player<\/a> to see this player.<\/div>');
var params={};
var attributes={};
var flashvars = {};
params["scale"]="noborder";
params["play"]="true";
params["menu"]="true";
params["loop"]="true";
params["allowfullscreen"]="true";
params["wmode"]="opaque";
params["allowscriptaccess"]="sameDomain";
attributes["id"]="monoslideshow";
attributes["title"]="Impressionen";
attributes["name"]="monoslideshow";
flashvars["dataFile"]="
http://www.inselhaus-foehr.de/media/flash/monoslideshow.xml";
flashvars["showLogo"]="false";
flashvars["showRegistration"]="false";
swfobject.embedSWF("
http://www.inselhaus-foehr.de/media/flash/monoslideshow.swf", "flash2011516225758", 600, 300, "7.0.0", false, flashvars, params, attributes);
/*]]>*/
</script></p></p>
</div>
</div>
Hope this can help anybody!
Corinna