pam authentication not working.

[balu phani kumar <balu enigma gmail com>]

hi,
 i installed svn,trac and i want to access through browse with pam
 authentication so i installed pam modules added to httpd.conf

LoadModule auth_pam_module   /usr/lib/httpd/modules/mod_auth_pam.so
LoadModule auth_sys_group_module /usr/lib/httpd/modules/
mod_auth_sys_group.so

and in /etc/pam.d/httpd

##%PAM-1.0
auth       required     /lib/security/pam_unix.so
account    required     /lib/security/pam_unix.so

and trac.conf is
<Location /svn/trac/first_pro>
    SetHandler mod_python
    PythonHandler trac.web.modpython_frontend
    PythonOption TracEnv /svn/trac/first_pro
    PythonOption TracUriRoot /svn/trac/first_pro
    AuthType Basic
    AuthName "trac browser"
    AuthPAM_Enabled on
    AllowOverride None
    Require group svnaccess
    Require valid-user
</Location>

i was given full permissions for trac and svn folder (for testing).
like
drwxrwxrwx 10 root svnaccess   4096 Jul 19 17:05 first_pro
(for testing) even it is not working and balu is member of svnaccess
group.

so when i try to browse it asking username and password after that is
 is giving 401 authorization required.
"
This server could not verify that you
are authorized to access the document
requested.  Either you supplied the wrong
credentials (e.g., bad password), or your
browser doesn't understand how to supply
the credentials required.

---

Apache/2.2.3 (Red Hat) Server at 192.168.2.61 Port 80
"

in /http/log/error.log
i found

[Mon Jul 20 12:00:55 2009] [error] [client 192.168.2.42] PAM: user 'phaneendra.gb'  - invalid account: Permission denied

please help me.