I have script at http://www.domain.com/frederick/htdocs/index.php
its webmail script, but its very dificutl to remember all.

I have created subdomain mail.domain.com
How i can do that when i go to mail.domain.com then it will go to above address

something like a .htaccess file uploaded to the subdomain directory...

RewriteEngine on
RewriteBase /
RewriteRule ^(.*)$ http://www.domain.com/frederick/htdocs/index.php/$1

-might do the trick. Lots of differnet rewrite and redirect lines for various things...

Or you could make a .htaccess file for that directory and put just this in it:

Redirect / http://www.domain.com/frederick/htdocs/index.php

this long url $ other subdomain both are base on same domain, does cpanel dont allow me to do this, I mean redirect ?