After updating the headers manually, in IE 6 or Firefox 2.0.0.4 (and possibly other versions), the browser will display the following...
Reading Headers in alt.binaries.test:
1000 in 0.87s(3762479/3789480)|1999 in 1s(3763479/3789480)|2998 in 1.57s(3764479/3789480)|3996 in 0.67s(3765479/3789480)|4994 in 0.66s(3766479/3789480)|5985 in 0.7s(3767479/3789480)|6966 in 0.93s(3768479/3789480)|7959 in 0.97s(3769479/3789480)|8951 in 0.72s(3770479/3789480)|9950 in 0.76s(3771479/3789480)|10950 in 0.6s(3772479/3789480)|
Done!
It will then sit at that screen indefinitely.
In order to re-access the admin interface, you must close the browser (or switch to a different one, i.e. Firefox > IE)
Seems to have something to do with the session getting stuck because you cannot go back and get a previous page either.