I can reliably trigger this error on Ubuntu Natty (Python 2.7.1+)
as well as on Debian 6 (Python 2.6.6).

Find below the exact commands that I issued to install and produce this
seemingly buggy behaviour.

ROUNDUPBASE=/home/hemmecke/scratch/roundup
ROUNDUP=$ROUNDUPBASE/local  ## target directory
ROUNDUPSRC=$ROUNDUPBASE/src ## roundup sources)
V=1.4.19                    ## roundup version number
mkdir -p $ROUNDUPSRC
cd $ROUNDUPSRC

wget http://pypi.python.org/packages/source/r/roundup/roundup-$V.tar.gz
tar xzvf roundup-$V.tar.gz
mv roundup-$V roundup
cd roundup

python setup.py install --prefix=$ROUNDUP
export PATH=$ROUNDUP/bin:$PATH

TRACKERS=$ROUNDUPBASE/trackers
mkdir -p $TRACKERS
cd $ROUNDUPBASE

$ROUNDUP/bin/roundup-admin install
Enter tracker home: /home/hemmecke/scratch/roundup/trackers/foo
Templates: classic, minimal, devel
Select template [classic]: 
Back ends: anydbm, sqlite
Select backend [anydbm]: 

# put the attached config.ini to
# /home/hemmecke/scratch/roundup/trackers/foo
#---------------------------------------------
# or change the original config.ini in the following places:
[main]
admin_email = foo@example.com
dispatcher_email = foo@example.com
email_registration_confirmation = no
[tracker]
web = http://localhost:9112/foo/
email = foo@example.com
[mail]
host = example.com
username = foo
password = secret
#---------------------------------------------

$ROUNDUP/bin/roundup-admin initialise
Enter tracker home: /home/hemmecke/scratch/roundup/trackers/foo
Admin Password: 
       Confirm: 

$ROUNDUP/bin/roundup-server -p 9112 -d $TRACKERS/issues.pid -l
$TRACKERS/issues.log foo=$TRACKERS/foo

#-----------------------------------------------------------------
Point your browser to http://localhost:9112/
Login as admin
Create a new user "foo" (set passwort to 123, set email
log out

log in as new user "foo"
click "Your Details"
enter new password "abc"
enter confirm password "abc"
click "Submit Changes".

After about 3-5 seconds you'll see:
=========
An error has occurred

A problem was encountered processing your request. The tracker
maintainers have been notified of the problem.
=========

The mail text that arrived at my admin account is attached.

Ralf