Redirect subdomain to subdirectory

i've already read all topics here and on google about redirection but i'm a programmer and i cant get it going.

I have Apache 2.2 installed. The web root is C:\Apache\htdocs. My network admin set me up a local domain that points to the server with Apache. The domain is myPhpApp.ourcompany.local. And this subdomain works, it shows the Apache "It works" page.

Now i have a website in C:\Apache\htdocs\myPhpApp and i want Apache to redirect the myPhpApp.ourcompany.local to this directory. The URLs should stay while browsing the website always as myPhpApp.ourcompany.local for example: myPhpApp.ourcompany.local/index.php, myPhpApp.ourcompany.local/data.php and so on.

I dont know how to achieve this? Mod-rewrite, virtual hosts, combination of both? i have got this and this does not work:

<VirtualHost myphpapp.ourcompany.local>
DocumentRoot /myphpapp/
ServerName www.example1.com

RewriteEngine on
RewriteRule   ^/$  /myphpapp/  [R]

</VirtualHost>

In effect i get:

Forbidden

You don't have permission to access /myphpapp/ on this server. Can anyone help?

EDIT Maybe i forgot to mention: i dont put this into the www root which is C:/Apache/htdocs becuase i have more apps开发者_JS百科 in there. i have 3 directories in thdocs: myphpapp, myoldapp, mytestapp. As a target i want to have 3 subdomains that point to each directory.

I think it will be a combination of Nikola's and cromestant's answers:

<VirtualHost *:80>
    DocumentRoot "C:/Apache/htdocs/myPhpApp"
    ServerName myPhpApp.ourcompany.local
</VirtualHost>

First of all, you don't need a rewrite rule for simple thing as this. I assume you need following VirtualHost definition

<VirtualHost *>

    DocumentRoot /myphpapp/
    ServerName myphpapp.ourcompany.local

</VirtualHost>

"VirtualHost *" part tells Apache on which interface and optionally port to listen to. ServerName tells which domain name will be used to identify this virtual host.

Document root in your apache config should point to your directory where you have the app, in what you stated in your question it should be

DocumentRoot C:\Apache\htdocs\myPhpApp

and that is all. restart or reload your apache, and test.