Comment 5 for bug 947738

> Mar 6 05:00:35 ubuntu ubiquity: sudo: unable to open /etc/sudoers: Permission denied

That's a very strange error. sudo should be an suid-root executable, which means it should have no problem opening /etc/sudoers.

Is this happening when installing from a live CD or from a USB stick? What's the output of the command 'ls -l /usr/bin/sudo' on this system? (Have you already rebooted since hitting this error, and if so, did the problem persist?)

I suspect a filesystem corruption problem or kernel fs driver bug here. The above answers may help us pin it down.