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Okay, understood. Just found the solution by re-reading your comment above. I didn't pay attention to the fact that you have different Ubuntu/Debian repos. I must have copied the repo address from another page, inadvertently.
Today I upgraded my system and python-passlib was upgraded from your repo. I reverted it back. Is it mandatory that you provide this package? I don't know, maybe I'm (not) the only one facing this specific issue?
  Installed: 1.5.3-2
  Candidate: 1.5.3-2
  Version table:
 *** 1.5.3-2 0
        500 main/ubuntu i386 Packages
        100 /var/lib/dpkg/status
     1.5.3-0ubuntu3 0
        500 trusty/main i386 Packages
I started from scratch again and installed python-passlib from the Ubuntu repo prior to installing Ajenti. It seems it's okay now.
Package: python-passlib
Version: 1.5.3-1~bpo60+1

Apt shows that the package is installed but the python import gives this:

  File "", line 1, in 
ImportError: No module named pass lib

I don't know why this is happening now because it's a fresh install. And when I installed my dev server a few days ago it didn't happen and the Ajenti install was smooth...
This is the error I have:
Traceback (most recent call last):
  File "/usr/bin/ajenti-panel", line 124, in <module>
    from ajenti import core
  File "/usr/lib/pymodules/python2.7/ajenti/", line 21, in <module>
    from ajenti.middleware import SessionMiddleware, AuthenticationMiddleware
  File "/usr/lib/pymodules/python2.7/ajenti/", line 11, in <module>
    from ajenti.users import UserManager
  File "/usr/lib/pymodules/python2.7/ajenti/", line 3, in <module>
    from passlib.hash import sha512_crypt
ImportError: No module named passlib.hash

The weird thing when I try to restart Ajenti is that it says that it's not running and start. But when I redo the restart, it's actually not running:

# service ajenti restart
Stopping Ajenti:
 * not running
Starting Ajenti:
22.08.2014 16:22 INFO  Using config file /etc/ajenti/config.json
 * started
# service ajenti restart
Stopping Ajenti:
 * not running
Starting Ajenti:
22.08.2014 16:23 INFO  Using config file /etc/ajenti/config.json
 * started