I guess this can go in "scene" hopefully. About 6 months ago I downloaded MUI from Gulliver's site and it worked fine. I think when I installed it in my Amiga 4000, I got it from aminet. Well, I am pretty pretty sure both those files have somehow gotten corruputed.
This guy's link however: http://guide.abime.net/wb3.1/chap6.htm
contains a fully working demo version (still needs keyfile). If anyone who does maintainence on aminet sees this, you might want to get that version up there. And I download strictly to my Amiga when I get Amiga formatted files. The LHA never touches my PC.