When I assign a bug on creation I get:
-------------------------------------------------------------
Traceback (most recent call last):
  File
"/usr/lib/python2.2/site-packages/roundup/cgi/client.py",
line 777, in newItemAction
    nid = self._createnode(props)
  File
"/usr/lib/python2.2/site-packages/roundup/cgi/client.py",
line 1056, in _createnode
    return cl.create(**props)
  File
"/usr/lib/python2.2/site-packages/roundup/backends/back_anydbm.py",
line 893, in create
    self.fireReactors('create', newid, None)
  File
"/usr/lib/python2.2/site-packages/roundup/backends/back_anydbm.py",
line 1869, in fireReactors
    react(self.db, self, nodeid, oldvalues)
  File
"/usr/lib/python2.2/site-packages/roundup/templates/classic/detectors/nosyreaction.py",
line 42, in nosyreaction
    raise roundupdb.DetectorError, message
DetectorError: Couldn't send confirmation email:
mailhost (111, 'Connection refused')
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this only happens if the bug has a change note.
if I create an item, and either add the change note or
assign after creation, it works fine.

I suspect this might be due to the fact that I don't
have a working mail server.  I configured my system to
"mock" email until I find the time to setup my mail server.

You can test against my server at:
http://144.82.31.201/cgi-bin/roundup.cgi/toontalk/

But please notify me!!! (y.mor@ioe.ac.uk)

Logged In: YES 
user_id=6405

You have not configured your MAILHOST variable in your 
tracker config.py correctly. 
 

Logged In: YES 
user_id=667764

I just spent half a day fooling around with roundup's mail
settings.
The problem is, I need to use the institutional mail server,
which requires user:pwd for smtp.  Couldn't find any way to
configure that into roundup.

Logged In: YES 
user_id=6405

OK, I'm pretty sure I've fixed this in the current CVS. You'll need to 
set an additional config.py variable (just under the MAILHOST 
specification would do: 
 
# If your SMTP mail host requires a username and password for 
access, then 
# specify them here. 
#MAILUSER = ('username', 'password') 
 
And then everything should work. 
 
I've added TLS support too while I was at it.