This appears to be a ubiquity problem. It's crashing in ubiquity-dm due to gir problems. ubiquity-dm is trying to call GdkPixbuf.render_pixmap_and_mask but it isn't being found.
The X log error message doesn't seem to be relevant, as when I commented out the crashy bits in ubiquty-dm, X came up (and then metacity crashed, leading ubiquity to gracefully give up and autologin to a desktop).
This appears to be a ubiquity problem. It's crashing in ubiquity-dm due to gir problems. ubiquity-dm is trying to call GdkPixbuf. render_ pixmap_ and_mask but it isn't being found.
The X log error message doesn't seem to be relevant, as when I commented out the crashy bits in ubiquty-dm, X came up (and then metacity crashed, leading ubiquity to gracefully give up and autologin to a desktop).
This is bug 830061. I'll mark as a dup.