Recently created topics in SlideShare tagged with api

i would like to use the slideshare api to upload a ppt file on demand.. but i keep getting the following error message:
<slideshareserviceerror>
<message>6: Slideshow file is not a source object</message>
</slideshareserviceerror>

Here is the URL i am trying (obviously replaced certain details!)

http://www.slideshare.net/api/1/uploa...

If anyone can help me that would be great.

i am getting invalid api validation error..
the code what i have written is...
<?php echo"<form action='http://www.slideshare.net/api/1/upload_slideshow' method='post' ENCTYPE='multipart/form-data?>";
echo"username:<input name="username" type="text" /><br />";
echo"password:<input name="password" type="password" /><br />";
$ts=time();
$api_key='N7BBoxsa';
$hash=eDlUiCYC."$ts";
$slideshow_title=" api-conference-2008";
echo"<input name="api_key" type="hidden" value="$api_key" /><br />";
echo"<input name="ts" type="hidden" value="$ts" /><br />";
echo"<input name="hash" type="hidden" value="$hash" /><br />";
echo"<input name="slideshow_title" type="hidden" value="$slideshow_title" /><br />";
echo"<input name="slideshow_srcfile" type="file" /><br />";
echo"<input name="slideshow_description" type="hidden" />" ;
echo"<input name="submit" type="submit" value="submit" />";
echo"";

I recently signed up for the SlideShare API and received an API key and a shared secret. When I finally got around to playing with the API, I'm getting an error indicating that there's a problem verifying my API key or shared secret.

I posted on the google group, but this list seems to be dead. I've also emailed SlideShare through the contact form on the website and I still haven't gotten any response. I tried applying for a new API key and I haven't received any response from that.

Is there somebody on this list that works for SlideShare that can help me out with this? I love your site and would love to use your API, if I could only get it to work.

Thanks,

Michael Collins