I have gotten this same error when using the live dvd after making 2 different remasters using
umount -a
remastermeas root.
I booted it in virtualbox to take a screenshot

Does anybody know what it could be? I made the remaster in virtualbox with kernel 2.6.26 and kde4. I am doing this because i want to make a remaster of kde4 with an older kernel because support for my wireless card was messed up around 2.6.29. I can't do it as an upgrade from straight 2009.2 outside of virtualbox because 2009 has messed up wireless tools. This virtualbox has a 20 gb root and 4 gb home with 3.5 gb used on root. The iso produced was approx 1gb.