Installing ShellExample causes Announcer to break

[anonymous]

When ShellExample is added to my Trac, I then get announver errors like this;

2012-03-12 17:17:57,519 Trac[api] ERROR: AnnouncementSystem failed.
Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/announcerplugin/api.py", line 369, in _real_send
    distributor.distribute(transport, packages[transport], evt)
  File "/usr/lib/python2.4/site-packages/announcerplugin/distributors/email_distributor.py", line 238, in distribute
    self._do_send(transport, event, k, v, fmtdict[k])
  File "/usr/lib/python2.4/site-packages/announcerplugin/distributors/email_distributor.py", line 314, in _do_send
    output = formatter.format(transport, event.realm, format, event)
  File "/usr/lib/python2.4/site-packages/announcerplugin/formatters/ticket_email.py", line 97, in format
    return self._format_html(event)
  File "/usr/lib/python2.4/site-packages/announcerplugin/formatters/ticket_email.py", line 215, in _format_html
    dirs += provider.get_templates_dirs()
TypeError: iteration over non-sequence

Removing the ShellExample plugin allows announcer to work as before.

We are using the following on Postgres

Trac 0.12.3
agilo 0.9.6.2
Bitten 0.6.1dev-r1009
ShellExampleProcessor 0.12.2 (disabled)
SlideShow 0.2
TracAccountManager 0.3.2
TracAnnouncer 0.11.1-r10458
TracWysiwyg 0.12.0.4-r11158
TracXMLRPC 1.1.2-r11306
TypedTicketWorkflow-plugin 0.1dev-r4791