Hm, it seems that I forced it work somehow.
So, the problem was updating a firmware using Internet Explorer. You should use Firefox instead (Chrome not as well).
I have upgraded my firmware from 2.11 to 2.14 and FOR NOW
![Smiley :)](http://forums.dlink.com/Smileys/default/smiley.gif)
it seems all works fine. Obtaining IP address problem disappeared.