Also ran into this problem--

The following packages will be upgraded:
  bzr python-apt update-manager update-manager-core
4 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
Need to get 0B/5523kB of archives.
After this operation, 434kB of additional disk space will be used.
Do you want to continue [Y/n]? y
(Reading database ... 238977 files and directories currently installed.)
Preparing to replace python-apt 0.7.4ubuntu4 (using .../python-apt_0.7.4ubuntu5_i386.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pycentral", line 1593, in <module>
    main()
  File "/usr/bin/pycentral", line 1587, in main
    rv = action.run(global_options)
  File "/usr/bin/pycentral", line 1075, in run
    requested = pyversions.requested_versions_for_runtime(version_field, version_only=True)
  File "/usr/share/pycentral-data/pyversions.py", line 172, in requested_versions_for_runtime
    vinfo = parse_versions(vstring)
  File "/usr/share/pycentral-data/pyversions.py", line 58, in parse_versions
    raise ValueError, 'error parsing Python-Version attribute'
ValueError: error parsing Python-Version attribute
dpkg: error processing /var/cache/apt/archives/python-apt_0.7.4ubuntu5_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Preparing to replace update-manager 1:0.87.6 (using .../update-manager_1%3a0.87.8_all.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pycentral", line 1593, in <module>
    main()
  File "/usr/bin/pycentral", line 1587, in main
    rv = action.run(global_options)
  File "/usr/bin/pycentral", line 1075, in run
    requested = pyversions.requested_versions_for_runtime(version_field, version_only=True)
  File "/usr/share/pycentral-data/pyversions.py", line 172, in requested_versions_for_runtime
    vinfo = parse_versions(vstring)
  File "/usr/share/pycentral-data/pyversions.py", line 58, in parse_versions
    raise ValueError, 'error parsing Python-Version attribute'
ValueError: error parsing Python-Version attribute
dpkg: error processing /var/cache/apt/archives/update-manager_1%3a0.87.8_all.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Preparing to replace update-manager-core 1:0.87.6 (using .../update-manager-core_1%3a0.87.8_i386.deb) ...
Traceback (most recent call last):
  File "/usr/bin/pycentral", line 1593, in <module>
    main()
  File "/usr/bin/pycentral", line 1587, in main
    rv = action.run(global_options)
  File "/usr/bin/pycentral", line 1075, in run
    requested = pyversions.requested_versions_for_runtime(version_field, version_only=True)
  File "/usr/share/pycentral-data/pyversions.py", line 172, in requested_versions_for_runtime
    vinfo = parse_versions(vstring)
  File "/usr/share/pycentral-data/pyversions.py", line 58, in parse_versions
    raise ValueError, 'error parsing Python-Version attribute'
ValueError: error parsing Python-Version attribute
dpkg: error processing /var/cache/apt/archives/update-manager-core_1%3a0.87.8_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Preparing to replace bzr 1.0-1 (using .../bzr_1.1~rc1-1_i386.deb) ...
Ignoring nonregistered document `bzr'
Traceback (most recent call last):
  File "/usr/bin/pycentral", line 1593, in <module>
    main()
  File "/usr/bin/pycentral", line 1587, in main
    rv = action.run(global_options)
  File "/usr/bin/pycentral", line 1075, in run
    requested = pyversions.requested_versions_for_runtime(version_field, version_only=True)
  File "/usr/share/pycentral-data/pyversions.py", line 172, in requested_versions_for_runtime
    vinfo = parse_versions(vstring)
  File "/usr/share/pycentral-data/pyversions.py", line 58, in parse_versions
    raise ValueError, 'error parsing Python-Version attribute'
ValueError: error parsing Python-Version attribute
dpkg: error processing /var/cache/apt/archives/bzr_1.1~rc1-1_i386.deb (--unpack):
 subprocess pre-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/python-apt_0.7.4ubuntu5_i386.deb
 /var/cache/apt/archives/update-manager_1%3a0.87.8_all.deb
 /var/cache/apt/archives/update-manager-core_1%3a0.87.8_i386.deb
 /var/cache/apt/archives/bzr_1.1~rc1-1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)