Hi toplisek, good to see you again. From memory you are supporting older versions of ie, so just recall ie<7 does not support position:fixed - which may be the issue. Hence DrDoc asking for versions and doctype.
@DrDoc. What can I say? "Welcome back" sounds like the boarder opening the door to the home-owner! It's just fantastic to see you again, and (metaphorically speaking) the chair with your name on has been empty for too long - please dust it off, make yourself comfortable and stay a while!