problem hiding headlines/links

I am unable to hide a headline or link from the "show all" listing ("show all" under the headlines and links heading-not "view all" mode). It has the circling red dots, but the headline  is not removed. When I remove a headline  from the main page (that shows only 6 at a time), the headline is hidden and the blue message appears saying that it has been removed, but when I then try to see the next set of headlines by clicking a number at the bottom, I am given a collectivex 404 error:

That page couldn't be found.. if you came here from another site, check the URL and try again; otherwise, perhaps that item has been deleted?

Use the Back Button on your browser to return to the previous page.

If I reload the page after hiding a headline, I am able to click to see the next set without getting the error message.

(Also the 404 error appears over the summary page but is floating on top of some areas and behind others and looks pretty ugly).