Mine

root@chuck:~# su proxy -c "/usr/local/bin/squid-redirector.py"
Traceback (most recent call last):
  File "/usr/local/bin/squid-redirector.py", line 43, in <module>
    logging.basicConfig(filename=LOG_FILENAME,level=LOGLEVEL,format='%(asctime)s %(levelname)s %(message)s',datefmt='%d/%m/%Y %H:%M:%S')
  File "/usr/lib/python2.6/logging/__init__.py", line 1402, in basicConfig
    hdlr = FileHandler(filename, mode)
  File "/usr/lib/python2.6/logging/__init__.py", line 827, in __init__
    StreamHandler.__init__(self, self._open())
  File "/usr/lib/python2.6/logging/__init__.py", line 846, in _open
    stream = open(self.baseFilename, self.mode)
IOError: [Errno 13] Permission denied: '/root/squid-redirector.log'