The mapmixer site (mapmixer.oceaniaut.com) has mysteriously disappeared. My guess is the magic host fairies haven't re-registered the domain. I'll use the excellent resources here to act as the new location for the hosting of the mapmixer releases.
I'll make the 3.01 Final Release available when I get time. For now, you can email me at the usual address provided on this page. I'm going to have to work out what to do with all the online documentation I created :\
While I still have respect for the game, I've nearly lost my entire interest for the project. Time will tell.
If you're still playing UT3 and using mapmixer, send me an email.