Hi,
Did somebody meet such build error?
installing base-files
rmdir: failed to remove `/var/run': Directory not empty
dpkg: error processing base-files (--install):
subprocess installed post-installation script returned error exit status 1
Processing triggers for install-info ...
Errors were encountered while processing:
base-files
exit ...
It happens for xUbuntu 11.10 only 
Thanks,
Alex