Removal of urls in Webmaster Tools

[Gemini23]

I have about numerous urls that I would like to remove from Google WMT with urls removed (deleted and no lonegr exist) from my website dating back over a year. The web pages have long since gone and they were hosted on my website. When I try to go through the process of removing them it is 'Denied' with the message:
"The content you submitted for cache removal appears on the live third-party page.
As you may know, information in our search results is actually located on third-party, publicly available webpages. Even if we removed this page from our index, the content in question would still be available on the web.
To remove this information from our search results and from the web, you'll need to contact the webmaster of this third-party site. Once the webmaster makes the change, you can submit a request to remove the cached copy or simply wait for our search results to reflect this change the next time we crawl the page.

The website shown is mine and the content does not appear on any third party page. THe following is part of the removal text by Google.
To remove a page or image, you must do one of the following:

Ensure requests for the page return an HTTP status code of either 404 or 410 OR
Ensure that the pages you want to remove have been blocked using a robots.txt file OR
Ensure that the pages you want to remove have been blocked using a meta noindex tag.

The pages all show a 404.

Can anyone suggest what I am doing wrong?

[tedster]

Have you verified that those exact urls (character for character) get a 404 status code from your server in the http header?

[Gemini23]

the urls are 404 definitely. part of the text in WMT quotes.. "...Even if we removed this page from our index, the CONTENT in question would still be available on the web." (mycapitals) Does that mean that if another url exists with that content on, then the 404 cannot be 'removed' from Google WMT web crawl and that the only thing to do is re-create that url (file name)and write a re-direct? to the current url. OR should it be possible to remove?

[edited by: Gemini23 at 9:43 pm (utc) on Feb. 18, 2009]

[tedster]

Hmmmm... this may be a new WMT bug of some kind. There's a similar report yesterday in our Robots.txt forum

[webmasterworld.com...]

It sounds like a buggy mash-up between a request for a cached page removal [google.com] and a url removal request in WMT.