this report has been filed here:

https://bugs.edge.launchpad.net/ubuntu/+source/telepathy-butterfly/+bug/604806

This is on telepathy-butterfly 0.5.12.

"When I quit empathy (signed in with google talk, msn and local network chat), telepathy-butterfly crashed and asked me to send this bug report."

traceback:

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/butterfly/util/decorator.py", line 87, in async_function
    func(*args, **kwargs)
  File "/usr/lib/telepathy/telepathy-butterfly", line 67, in quit
    manager.quit()
  File "/usr/lib/python2.6/dist-packages/butterfly/connection_manager.py", line 87, in quit
    conns = self._connections[:]
TypeError: 'set' object is unsubscriptable