We have the same issues on our site as well. Permissions were already 755 but reset them again just to be sure, and having the same issue. We have a very large gallery and a ton of photos, so I suspect that may be part of the issue.
Plugin doesn’t hang when I load options panels or things like that, but it takes a couple minutes to load /admin.php?page=galleries_bwg and really any function dealing with actually adding images and galleries. We have 1894 items in the gallery right now, if that helps.
