This as the result of a package becoming corrupt on your file system or in memory:
Mar 28 20:00:51 ubuntu ubiquity: Preparing to unpack .../language-pack-en-base_1%3a14.04+20150219_all.deb ...
Mar 28 20:00:51 ubuntu ubiquity: Unpacking language-pack-en-base (1:14.04+20150219) over (1:14.04+20140707) ...
Mar 28 20:00:51 ubuntu ubiquity: dpkg-deb (subprocess): decompressing archive member: lzma error: compressed data is corrupt
Mar 28 20:00:51 ubuntu ubiquity: dpkg-deb: error: subprocess <decompress> returned error exit status 2
Mar 28 20:00:51 ubuntu ubiquity: dpkg: error processing archive /target/var/cache/apt/archives/language-pack-en-base_1%3a14.04+20150219_all.deb (--unpack):
Mar 28 20:00:51 ubuntu ubiquity: subprocess dpkg-deb --fsys-tarfile returned error exit status 2
Mar 28 20:00:51 ubuntu ubiquity: No apport report written because the error message indicates an issue on the local system
This as the result of a package becoming corrupt on your file system or in memory:
Mar 28 20:00:51 ubuntu ubiquity: Preparing to unpack .../language- pack-en- base_1% 3a14.04+ 20150219_ all.deb ... pack-en- base (1:14.04+20150219) over (1:14.04+20140707) ... var/cache/ apt/archives/ language- pack-en- base_1% 3a14.04+ 20150219_ all.deb (--unpack):
Mar 28 20:00:51 ubuntu ubiquity: Unpacking language-
Mar 28 20:00:51 ubuntu ubiquity: dpkg-deb (subprocess): decompressing archive member: lzma error: compressed data is corrupt
Mar 28 20:00:51 ubuntu ubiquity: dpkg-deb: error: subprocess <decompress> returned error exit status 2
Mar 28 20:00:51 ubuntu ubiquity: dpkg: error processing archive /target/
Mar 28 20:00:51 ubuntu ubiquity: subprocess dpkg-deb --fsys-tarfile returned error exit status 2
Mar 28 20:00:51 ubuntu ubiquity: No apport report written because the error message indicates an issue on the local system