WordPress MU

Is this possible with RC4?
I've tried to install MU into my website http://www.name.com/wpmu/
Everything is ok but when i try to load this address browser is redirected to
name.com/wpmu/
and then to name.com
...and after all to http://www.name.com
end.

Why?
This is my .htaccess file (I've also put <directory> directive at the end).
I've also tried to remove it but it says "this blog does not exist try name.com/wpmu"
Is there a solution to this problem?!

RewriteEngine On
RewriteBase /wpmu/

# Rewrite http://www.domain.com to domain.com
RewriteCond %{HTTP_HOST} ^www\.(.*)
RewriteRule ^(.*) http://%1/$1 [R,L]

#uploaded files
RewriteRule ^(.*)?/?files/(.*) wp-content/blogs.php?file=$2 [L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-.*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

<Directory /opt/muwp>
AddType application/x-httpd-php .php .php3 .phtml
AddType application/x-httpd-php-source .phps
php_admin_value open_basedir /opt/muwp
Options None
Options +Indexes
Options +Includes
Options +FollowSymLinks
AllowOverride All
order deny,allow
deny from all
allow from all
</Directory>

I've tried to install MU into my website http://www.name.com/wpmu/

Reread the instructions. If you're doing that, then you missed a couple of steps.

From readme:
http://codex.wordpress.org/Installing_WordPress

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If you want to have your WordPress installation in its own subdirectory on your web site (e.g. http://example.com/blog/), rename the directory wordpress to the name you'd like the subdirectory to have and move or upload it to your web server. For example if you want the WordPress installation in a subdirectory called "blog", you should rename the directory called "wordpress" to "blog" and upload it to the root directory of your web server.
-----------

and

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If you need to upload your files to your web server, rename the wordpress directory to your desired name, then use your favorite FTP client to upload the directory to your desired location within the root directory of your web site.
-----------

and nothing more about wp mu in subdirectories. is there another read me file or something like it? Tell me it because I've found only this.

You are not installing Wordpress, you are installing WordpressMU. There's a README.TXT in the download.