Go to your plugin manager and look for any forumadmin_edit_form hooks and disable them. See if that works. The save button is after that hook so there's probably faulty code in that hook.
I've got a long list , but this is what I guess I need to look into
any ideas what can I do now !?
PS: I did go to vbulletin.com and download vbulletin 4.2.2 again then I upload the file forum.php just trying to fix that issue but nothing happen and I don't know why i'm getting this "forum.php= File does not contain expected contents" even that I've just upload the file forum.php