wp-trackback giving 404 error

Hi,
Please help me with this as its showing alot of errors in webmasters. All the links are working fine except wp-trackbacks. I recently changed the permalinks from default to pretty permalinks (www.domainname.com/post id/postname)

Now recentl im gettin wp-trackback erroe showing :
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<response>
<error>1</error>
<message>I really need an ID for this to work.</message>
</response>

Any help would be appreciated.