Description of problem:
The koji package in F15 is unusable. Following the guides, it fails to function because /usr/lib/python2.7/site-packages/koji/db.py cannot import _quoteparams from pgdb

The file begins like so:
import logging
import sys
import pgdb
import time
import traceback
from pgdb import _quoteparams
assert pgdb.threadsafety >= 1
import context


if you comment out the line 'from pgdb import _quoteparams', it starts to function. 

According to http://lists.fedoraproject.org/pipermail/buildsys/2011-May/003656.html

This fixes the issue unless debugging is turned on.

To reproduce this, you would have to install koji from scratch on F15 and follow http://fedoraproject.org/wiki/Koji/ServerHowTo until you were asked to add the kojira user via koji command line.