Whats on functions.php on those lines? Is it a fresh install? Firstly i'd disable all plugins to see if it has an effect, Next i'd think it could be to do with permissions or php.ini settings, especially if it's on a fresh install/default theme/no mods
this problem automatically solve after reinstallation but now when i upload img using add media or post then there is no img and i find cross sign on img , upload dir is also empty. I do following things: - downgrading/upgrading - upload folder changing
Did this just stop working all of a sudden? Try to think of things you may have changed, did you change hosts, servers, etc..