Problem with Postgres authentification over apache

I'm on RHEL 5.4, and I've set up a Django project using PostgreSQL as the database (I've used MySQL before, but want to try something new :) ). When I run the Django test server, everything works, I can also connect trough the command line with password authentification:

psql -U myuser -h 127.0.0.1

But when I try to access my project over Apache, I get a 500 error code and this python traceback in apache's error log:

mod_wsgi (pid=7026): Exception occurred processing WSGI script '/var/www/myproject/myproject/hook.wsgi'.
Traceback (most recent call last):
  File "/var/www/myproject/myproject/src/django/django/core/handlers/wsgi.py", line 245, in __call__
    response = middleware_method(request, response)
  File "/var/www/myproject/myproject/src/django/django/contrib/sessions/middleware.py", line 36, in process_response
    request.session.save()
  File "/var/www/myproject/myproject/src/django/django/contrib/sessions/backends/db.py", line 55, in save
    obj = Session(
  File "/var/www/myproject/myproject/src/django/django/contrib/sessions/backends/base.py", line 152, in _get_session_key
    self._session_key = self._get_new_session_key()
  File "/var/www/myproject/myproject/src/django/django/contrib/sessions/backends/base.py", line 144, in _get_new_session_key
    if not self.exists(session_key):
  File "/var/www/myproject/myproject/src/django/django/contrib/sessions/backends/db.py", line 29, in exists
    Session.objects.get(session_key=session_key)
  File "/var/www/myproject/myproject/src/django/django/db/models/manager.py", line 132, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/var/www/myproject/myproject/src/django/django/db/models/query.py", line 336, in get
    num = len(clone)
  File "/var/www/myproject/myproject/src/django/django/db/models/query.py", line 81, in __len__
    self._result_cache = list(self.iterator())
  File "/var/www/myproject/myproject/src/django/django/db/models/query.py", line 269, in iterator
    for row in compiler.results_iter():
  File "/var/www/myproject/myproject/src/django/django/db/models/sql/compiler.py", line 672, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/var/www/myproject/myproject/src/django/django/db/models/sql/compiler.py", line 726, in execute_sql
    cursor = self.connection.cursor()
  File "/var/www/myproject/myproject/src/django/django/db/backends/__init__.py", line 75, in cursor
    cursor = self._cursor()
  File "/var/www/myproject/myproject/src/django/django/db/backends/postgresql_psycopg2/base.py", line 136, in _cursor
    self.connection = Database.connect(**conn_params)
OperationalError: could not connect to server: Permission denied
\tIs the server running on host "127.0.0.1" and accepting
\tTCP/IP connections on port 5432?

I checked the conn_params dictionary, it contains the correct username and password. My pg_hba.conf looks like this (I have the same exact configuration on an Ubuntu 9.04 server, where everything works peachy):

local   all         postgres                          ident
local   all         all                               md5
host    all         all         127.0.0.1/32          md5
host    all         all         ::1/128               md5

What am I doing wrong?