package supervisor (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Ryan Kaskel]

Binary package hint: supervisor

$ sudo apt-get install supervisor
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  python-medusa python-meld3
Suggested packages:
  python-medusa-doc
The following NEW packages will be installed:
  python-medusa python-meld3 supervisor
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 290 kB of archives.
After this operation, 1,552 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://mirror.ovh.net/ubuntu/ natty/universe python-medusa all 0.5.4+clean-2ubuntu1 [62.4 kB]
Get:2 http://mirror.ovh.net/ubuntu/ natty/universe python-meld3 amd64 0.6.5-3build1 [40.7 kB]
Get:3 http://mirror.ovh.net/ubuntu/ natty/universe supervisor all 3.0a8-1 [187 kB]
Fetched 290 kB in 0s (367 kB/s)
Selecting previously deselected package python-medusa.
(Reading database ... 268875 files and directories currently installed.)
Unpacking python-medusa (from .../python-medusa_0.5.4+clean-2ubuntu1_all.deb) ...
Selecting previously deselected package python-meld3.
Unpacking python-meld3 (from .../python-meld3_0.6.5-3build1_amd64.deb) ...
Selecting previously deselected package supervisor.
Unpacking supervisor (from .../supervisor_3.0a8-1_all.deb) ...
Processing triggers for ureadahead ...
Setting up python-medusa (0.5.4+clean-2ubuntu1) ...
Setting up python-meld3 (0.6.5-3build1) ...
Setting up supervisor (3.0a8-1) ...
Starting supervisor: Traceback (most recent call last):
  File "/usr/bin/supervisord", line 9, in <module>
    load_entry_point('supervisor==3.0a8', 'console_scripts', 'supervisord')()
  File "/usr/lib/pymodules/python2.7/supervisor/supervisord.py", line 371, in main
    go(options)
  File "/usr/lib/pymodules/python2.7/supervisor/supervisord.py", line 381, in go
    d.main()
  File "/usr/lib/pymodules/python2.7/supervisor/supervisord.py", line 94, in main
    self.run()
  File "/usr/lib/pymodules/python2.7/supervisor/supervisord.py", line 104, in run
    self.options.openhttpservers(self)
  File "/usr/lib/pymodules/python2.7/supervisor/options.py", line 1039, in openhttpservers
    self.httpservers = self.make_http_servers(supervisord)
  File "/usr/lib/pymodules/python2.7/supervisor/options.py", line 1242, in make_http_servers
    return make_http_servers(self, supervisord)
  File "/usr/lib/pymodules/python2.7/supervisor/http.py", line 799, in make_http_servers
    from web import supervisor_ui_handler
  File "/usr/lib/pymodules/python2.7/supervisor/web.py", line 29, in <module>
    import meld3
  File "/usr/lib/pymodules/python2.7/meld3/__init__.py", line 2, in <module>
    from meld3 import parse_xml
  File "/usr/lib/pymodules/python2.7/meld3/meld3.py", line 27, in <module>
    from xml.etree.ElementTree import fixtag
ImportError: cannot import name fixtag
invoke-rc.d: initscript supervisor, action "start" failed.
dpkg: error processing supervisor (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for python-support ...
Errors were encountered while processing:
 supervisor
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 11.04
Package: supervisor (not installed)
ProcVersionSignature: Ubuntu 2.6.35-28.50-generic 2.6.35.11
Uname: Linux 2.6.35-28-generic x86_64
Architecture: amd64
Date: Tue Jun 7 08:13:54 2011
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationMedia: Xubuntu 10.04 "Lucid Lynx" - Release amd64 (20100429)
SourcePackage: supervisor
Title: package supervisor (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to natty on 2011-04-28 (39 days ago)

[9johnny (s.j.)]

This is still an issue on ubuntu 11.04 server version.
Attached log is on a newly updated 11.04 server install, i have oly selected the "ssh server" task at installation so it's a very minimal install.
Link to related issue #749880