Yes, you have to login as Root. At least that was my experience with it. The way that I found best to do this was to boot normal., then when you see the Mandrake welcome screen hit CTRL+Backspace. This should kill the X session. Then, Hit CTRL+ALT+F1 and that should give you a terminal login prompt. Then simply login as Root.
If the system does not allow you to login as root you have the update your Security setttings.
You can do this by going to Mandrake Control Cetner --> Security --> Levels and Checks --> Click on System Options TAB. Then edit the config to allow direct ROOT login.
Hope that Helps!