Maybe it can save some time for somebody when I give my steps of handling that error. Or actually maybe somebody more code savvy person can take a look if this is actually cause and effect thing. Or happened somekind of mystics in my computer.

1) After installation I'll get error:
Notice: Undefined offset: 2 in drupal_http_request() (line 930 of /var/www/htdocs/includes/common.inc).

2) I create Like button dont count - no number (but it does recognise that im logged in and if some of my friends have liked a link and prints the names). Also like appears on my fb wall.

3) When on settings I enter API key, error disappears (even if for like button you dont need and API key).

4) Like button dont count.

5) I uninstall everything.

6) I enter API key before creating Like button.

7) Then creating preset for Like button and it works! Shows likes, counts