Comment 6 for bug 545470

The error you mention isn't really an error...That's a normal exit state for ureadahead-other, but it's init / upstart fault you're seeing that "error".

See following bugs:
Bug #484677 (where there is explained that it's normal behavior)
Bug #522197 (where there is a bug running against upstart for displaying it faulty)

So basically your system boots correctly and without errors if use the work-around of adding "nomodeset" as boot-option.

So the issue is that you have to apply the work-around to get your system running. How and why, I don't know, that's for someone else with more knowledge. :)