Comment 4 for bug 201768

Looks like you upgraded libc6 to the broken version 2.7-9ubuntu1 discussed in bug 201673. Marking this as a duplicate. In terms of fixing your system, if you have earlier versions of libc and probably libc-i686 in /var/cache/apt/archives, use dpkg -i [filenames] to downgrade to them. Bug 201673 and http://ubuntuforums.org/showthread.php?t=722886 have other suggestions for rebuilding a system, particularly if you rebooted it after this upgrade