Buggy tags?

Now I tried to post the news, included the habrakat tag, tried to use links. But when previewing the text "broke". The link was formed through the button "insert link", in this case an error. But just put a link in the editor, Habr could correctly arrange it.

And one more problem, when you try to follow the link www.habrahabr.ru/txt/html.html an error is displayed :

Habrawiki has a problem
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(Can't contact the MySQL server;); System error: 61 (10.0.0.2))