Hi all,
I'm a user of Debian 4.0. I installed apache 2.2 and add the functionality to support ~/public_html for each user. This is the permission of my public_html:
drwxr-xr-x 4 mj test 4096 2007-12-20 20:17 public_html
When I wanted to go through it and list the directory via my browser, it told me:

Access forbidden!

You don't have permission to access the requested directory. There is either no index document or the directory is read-protected.

If you think this is a server error, please contact the webmaster.
Error 403

But when I put index.htm in the public_html the browser can load it.
Where is the problem?

That seems to suggest directory listing is prohibited. For security reason, this is typically the default.

core - Apache HTTP Server

Look at the "Indexes" option.

I put this in /etc/apache2/mods-enabled and restarted the apache server.

lrwxrwxrwx 1 root root 32 2007-12-21 10:46 autoindex.load -> ../mods-available/autoindex.load

But nothing changed!

IIRC you need to add the Indexes option to the <Directory *> part of http.conf (or the conf file for your server - on Debian it may be under sites-{available|enabled}.

also, (I'm nowhere near a Debian system at the momen, so this may be wrong) I think the symlink you created has to start with a number, so try making it:

01-autoindex.load -> ../mods-available/autoindex.load

My problem was in file /etc/apache2/mods-available/userdir.conf
I put <Directory /home/*/*/public_html> from my previous server. And now I replaced it with <Directory /home/*/public_html> and every things becomes OK.

Thanx to all.

I've faced another problem with my Apache server.

I installed php5 php5-common php5-cli libapache2-mods-php.
After restarting apache, I couldn't run any php on my server. (even phpinfo())
It showed me:

Server error!

The server encountered an internal error and was unable to complete your request.

Error message:
Premature end of script headers: test.php

If you think this is a server error, please contact the webmaster.
Error 500