Google is getting on my nerves

[bholabhala]

I have uploaded my sitemap to google, and when i go to verify the sitemap, it gives me this error:
NOT VERIFIED
We've detected that your 404 (file not found) error page returns a status of 200 (OK) in the header.

I cant figure out, what going on. I have deleted all custome error pages, tried but still didn't work. There is something i noticed though, whenever i type:

[a href=\"http://www.mydomain.com/page_does_not_exist.html\" target=\"_blank\"]http://www.mydomain.com/page_does_not_exist.html[/a]
It takes me to the main page, its not redirection, i guess, because the URL does not change to [a href=\"http://www.mydomain.com\" target=\"_blank\"]http://www.mydomain.com[/a].

Any help will be highly appretiated.

Regards
Arslan
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