problem editing and posting with mars edit / ecto (wp1.5)

hi guys, i just upgraded my blog (hukl.geekheim.de) from 1.22 to 1.5 (Strayhorn) – everything seems to work fine but i cant use any of the blogging tools like mars edit and ecto to either post or edit something.

ecto gives me this output: Server error!

Method “mt.setPostCategories” produced a server error: “Sorry, you can not edit this post.”.

does the MoveableType api not work anymore – the console output looks like this:

Request with URL:
http://hukl.geekheim.de/xmlrpc.php
and data:
<?xml version=”1.0″ encoding=”UTF-8″?>
<methodCall>
<methodName>mt.setPostCategories</methodName>
<params>
<param>
<value><string>43</string></value>
</param>
<param>
<value><string>hukl</string></value>
</param>
<param>
<value><string>******</string></value>
</param>
<param>
<value><data>
<value><struct>
<member>
<name>categoryId</name>
<value><string>1</string></value>
</member>
</struct></value>
</data></value>
</param>
</params>
</methodCall>

Response:
<?xml version=”1.0″?>
<methodResponse>
<fault>
<value>
<struct>
<member>
<name>faultCode</name>
<value><int>401</int></value>
</member>
<member>
<name>faultString</name>
<value><string>Sorry, you can not edit this post.</string></value>
</member>
</struct>
</value>
</fault>
</methodResponse>

is this a permission or config problem ? anyone with similar expieriences ?