hi,
i have a problem i am using Cpanel web Hosting

When i Create Sub Domain and Upload Data to the Root website not open mean index.html page not open

For Example
When i open

http://webmaster.firstpk.com (its not working)

But

When i Type
http://webmaster.firstpk.com/index.html (Its working fine)

What is the Problem ? How i solve this ?

I am using simple CSS/HTML Webpages not any script etc

Please Help me

Probably index.html is not in the DirectoryIndex list for some reason or another.

It seems that you have not specified the default page for your domain. You will have to write below mentioned URL in your .htaccess file:

DirectoryIndex index.html