Problem with gallery and sidebar

I know It had been discussed but still I can't see where is the problem. I'm working on gallery2 on my site http://www.hoaxmag.com/magazyn/wpg2 . I made wpg2header.php by copying header.php and put it in the right directory. WPG2 validates the file. With proper header.php sidebar doesn't collapse with the gallery but when I use the file wpg2hear.php (as in the link) it collapses. Question is why? I need different sidebar for the gallery.

thanks for help Adam