eroux@norgz-laptop:~$ reportbug --debug

Detected character set: UTF-8
Please change your locale if this is incorrect.

Using 'Elie Roux <elie.roux@telecom-bretagne.eu>' as your from address.
Getting status for gregorio...
Checking for newer versions at packages.debian.org...
Will send report to Debian (per lsb_release).


No bug reports found.
Maintainer for gregorio is 'Elie Roux <elie.roux@telecom-bretagne.eu>'.
Looking up dependencies of gregorio...


Rewriting subject to 'gregorio: test'


Spawning sensible-editor...
Report will be sent to Elie Roux <elie.roux@telecom-bretagne.eu>


Traceback (most recent call last):
  File "/usr/bin/reportbug", line 1987, in <module>
    main()
  File "/usr/bin/reportbug", line 958, in main
    return iface.user_interface()
  File "/usr/bin/reportbug", line 1926, in user_interface
    severity, charset=charset, tags=tags)
  File "/usr/bin/reportbug", line 274, in handle_editing
    if not utils.mua_exists(utils.MUA[mailer]):
KeyError: -1