AttributeError: 'NoneType' object has no attribute 'rollback'

[vladsynkov@…]

I'm getting following error while trying to upgrade my DB.

That's happend after installing ComponentDependencyPlugin

Traceback is:

2010-06-29 15:02:07,642 Trac[console] ERROR: Exception in trac-admin
command:
Traceback (most recent call last):
 File "build/bdist.linux-i686/egg/trac/admin/console.py", line 107, in
onecmd
   rv = cmd.Cmd.onecmd(self, line) or 0
 File "/usr/lib/python2.6/cmd.py", line 218, in onecmd
   return self.default(line)
 File "build/bdist.linux-i686/egg/trac/admin/console.py", line 257, in
default
   return cmd_mgr.execute_command(*args)
 File "build/bdist.linux-i686/egg/trac/admin/api.py", line 123, in
execute_command
   return f(*fargs)
 File "build/bdist.linux-i686/egg/trac/env.py", line 790, in _do_upgrade
   self.env.upgrade(backup=no_backup is None)
 File "build/bdist.linux-i686/egg/trac/env.py", line 533, in upgrade
   with_transaction(self)(participant.upgrade_environment)
 File "build/bdist.linux-i686/egg/trac/db/api.py", line 82, in
transaction_wrapper
   ldb.rollback()
 File "build/bdist.linux-i686/egg/trac/db/util.py", line 102, in
__getattr__
   return getattr(self.cnx, name)
AttributeError: 'NoneType' object has no attribute 'rollback'

[anonymous]

Also having the same problem !