Wrong password everytime

Status changed to 'Confirmed' because the bug affects multiple users.

fresh install of 11.10
cannot log in because of "failed password"

When I try using the passwd command after booting rescue mode and going to a root prompt, I get this:

passwd: Authentication token manipulation error
passwd: password unchanged

I see this behavior on five(!) Aspire one D250-Netbooks with Ubuntu 12.04.1. It's not a typing problem - the password entered is just not recognized. On all machines are two different user accounts and this problem exists with each one, so it's not a account-specific problem. There's nothing uncommon in the logs. It is reproduceable with any user accounts created to test this. When trying often enough the login will work, but that can take up from one to twenty or thirty tries (there's no fix number whatsoever).

What seems to help sometimes is to use Ctrl+Alt+F1 and log in there, then switch back to graphical mode. Then the login works as normal. (This is not a workaround as it only works sometimes without any reason.)

When trying long enough and the login suddenly succeeds, it works normal for a few minutes (=using "sudo" in terminal and graphical system commands without a problem). But after a couple of minutes (5-10) the problem rises again.

Like I said I see this problem on all five machines. Besides everything works fine and there are no other problems with this machines and 12.04 I'm aware of.

I just downloaded a fresh 12.04.1 cd and installed it on a fresh, new system.

Odly enough the password didn't work to login the first time. But, afraid I misspelled the password (twice?, odd..) I tried a few different combinations of keys which are right next to the initial password. Trying over and over again, at once I logged on. Thinking I misspelled the password, I rebooted and booted to the Command Line root. Using the passwd [username] option it gave me the option to change the password.

Tried to change it, same as #4:

passwd: Authentication token manipulation error
passwd: password unchanged

Now a fresh install and auto-login to bypass the problem. Pretty serious, definately for new users who don't understand what's happening to them!