Trouble posting to blog from external blogging client

I have tried setting up Windows Live Writer and BlogDesk with no luck. During the configuration process, both clients fail at the step where they try to pull the available blog list. In Blogdesk, when I click "Get Blog-ID" I get the following error:

Error getting Blog-ID.
XML Parsing Error: Invalid procedure call or argument

Using fiddler I was able to get the drupal response returned to BlogDesk. It looks like something is putting extra blank lines before the line "<?xml version="1.0"?>". Can anyone confirm that the response is formatted incorrectly? If so, where would I start looking to see what is causing the issue? I've tried disabling modules but I keep getting the same error.

Thanks for any suggestions!

Here is the response to BlogDesk:

HTTP/1.1 200 OK
Cache-Control: store, no-cache, must-revalidate,post-check=0, pre-check=0
Content-Length: 455
Content-Type: text/xml
Expires: Sun, 19 Nov 1978 05:00:00 GMT
Last-Modified: Mon, 09 Nov 2009 22:55:17 GMT
Server: Microsoft-IIS/7.0
Set-Cookie: SESSebeb7304567b849632b9fa51a19887b3=deleted; expires=Sun, 09-Nov-2008 22:55:17 GMT; path=/
Set-Cookie: SESSebeb7304567b849632b9fa51a19887b3=hjqr1tscqb52kl5u010ujaok55; expires=Thu, 03 Dec 2009 02:28:38 GMT; path=/; domain=.mysite.com
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Date: Mon, 09 Nov 2009 22:55:17 GMT
Connection: close





<?xml version="1.0"?>

<methodResponse>
  <params>
  <param>
    <value><array><data>
  <value><struct>
  <member><name>url</name><value><string>http://www.mysite.com/index.php?q=blog/3</string></value></member>
  <member><name>blogid</name><value><string>blog</string></value></member>
  <member><name>blogName</name><value><string>Will: blog</string></value></member>
</struct></value>
</data></array></value>
  </param>
  </params>
</methodResponse>