I have enable mod_dir on my server.
It work fine for me following i had added in httpd conf:

<IfModule mod_userdir.c>

#UserDir disable
UserDir public_html

</IfModule>
<Directory /home/*/public_html>
Options Indexes Includes +FollowSymLinks +ExecCGI
AllowOverride All
Order deny,allow
Allow from all
AddHandler cgi-script .cgi .pl .plx .ppl .perl
</Directory>

I had done this settings for access:
http:\\mydomain.com\~user
It shows my user dir content. and i can run php and perl file also.
But when I access http:\\mydomain.com\demo.cgi(perlfile).
It gives me 500 internal error.
But when I run http:\\mydomain.com\~user\demo.cgi it allowed.
I want to access my perl file as http:\\mydomain.com\demo.cgi.
what more settings i have to make?
Shoud i have to add Alias?

What is your DocumentRoot set to?
Do you have a <Directory definition for your DocumentRoot dir?

For http:\\mydomain.com\demo.cgi
demo.cgi would need to be in your DocumentRoot dir not one of the users dirs.

You could probably symlink the DocumenRoot dir to one of the user dirs, but you still would need to have DocumentRoot defined and a <Directory setup much like the one you have for your users.

[QUOTE=rustek;4596682]What is your DocumentRoot set to?
==>> Documentroot set to /home/soft/www
Do you have a <Directory definition for your DocumentRoot dir?
yes i have.

My document root and userdir is the same

Look at your suexec.log, it may provide some insight into the error.