rwe121, your code on your wordpress page is:
<p><object width="550" height="400" align="middle" classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="https://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0" id="Slideshow"></p>
<param name="allowScriptAccess" value="sameDomain" />
<param name="movie" value="Slideshow.swf" />
<param name="quality" value="high" />
<param name="bgcolor" value="#ffffff" /></object>
If it was
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="https://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0" width="550" height="400" id="Slideshow" align="middle">
<param name="allowScriptAccess" value="sameDomain" />
<param name="movie" value="Slideshow.swf" /><param name="quality" value="high" /><param name="bgcolor" value="#ffffff" /><embed src="Slideshow.swf" quality="high" bgcolor="#ffffff" width="550" height="400" name="Slideshow" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="https://www.macromedia.com/go/getflashplayer" />
</object>
instead, like on your Slideshow.html example page, it would work.
Indeed, you need to be careful when using relative urls, particularly where WP will put your post in “yourdomain.xxx/archives/” so if your SSP file is going to be in the site root, you should specify things like <param name="movie" value="/Slideshow.swf" />
and <embed src="/Slideshow.swf" ...
, which precedes the filename with /, so that the file is not relative to the current directory but to the site root.
And it is important to specify the filename for both the param name value and the embed src value, sadly.