New install: root account is locked, starting shell

[Thierry Chatelet]

Hi list,
Made a new unstable install from daily build, using business card image from 2 
days ago. Everything went OK during the process, but the reboot was more 
trouble:
No way to enter the system as a user, login failed; no way to enter as root, 
login failed.
So I tried to boot safe mode, and I got this message: "root account is locked, 
starting shell". I dont no what to do from there. I tried to reinstall, but 
nothing changed. Any advice, wiki.... 
Thank's
Thierry