Open ftp://public.ftp.planetmirror.com/pub/lokigames/updates/mindrover/ with Konqueror and try to download any file. You'll be prompted for password. All these files can be downloaded without problems using Firefox.
the files download fine for me in konqueror - never asks for a password.
This works well for me too with kde 3.3.0
Odd, now it works for me too. Looks like it was a temporary server fault.