If you have found that you can not change project configurations and just get a "This page expects a form submission"
look no further. The problem is caused by that specific page loading JSON crap from Hudson"s java.net server which may be too slow.
Of course this is a braindead design (such things should be isolated in one "update stuff" page) but be thankfull for what works. ;-)
Workaround: Wait until the slow server has finally delivered (easy to spot on FF and Safari). If the server is down: Become a Hudson commiter and change it.
Update: This has been fixed by now