Webmaster Tools URL Removal Tool - why are some Denied?

[Bewenched]

Ok .. so google put up a new widget in Webmaster Tools to remove individual urls from the index.

To test it out there was a few pages that really didn't need to be there (total of 9) so I requested their removal.

Three were removed however 6 were denied. Now why would google refuse to delete pages that I requested? Our site is verified and their help center doesn't give reasons for denials.

Web page removal Denied

[Bewenched]

Anyone else have this happen?

[netmeg]

Do the pages return a 404?