[support] 'Sticky at top' not working for me

Hello, I've got a site running on Drupal 5.7 that sticky just doesn't work with. I've got 5 other sites using the same Drupal installation and none of them have this problem. I'm using a custom theme on that one, and I can't help but think it has something to do with the template. But, I have absolutely no idea where to even start on this one. Any ideas why Stick at top wouldn't work? (it does this for all content types) - jody