Comment 2 for bug 995159

The dpkg log attached to your bug report includes only this line, repeated over and over:

  Can not write log, openpty() failed (/dev/pts not mounted?)

So there's not enough information here to track down this issue. We would need a proper dpkg log to understand what's happening here.

(It's even possible that the /dev/pts error is itself the cause of this configuration failure.)