Sometime Today, SM cobbled together some glyphs to say:
Ubuntu 5.04 did not create a root password so it had to be created by booting into recovery mode. Even then, in the user mode gui, it does not accept the root password for admin utilities and says 'password incorrect'.
After an Ubuntu install, use sudo passwd root to change the root password as normal user. You can login to X as root by selecting the right option in Administration>>Login Screen Setup.
That's bad advice. Ubuntu did not create a root password for a good reason. You should NEVER log in as root. Ubuntu comes with sudo preinstalled and set up. Learn to use it.
Logging in to X as root? No, please don't.