.htaccess FILE HELP . . . where is my error in the code ?

Here is my code i am trying to use :

Options +FollowSymlinks
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /

#handle
RewriteCond %{HTTP_HOST} ^(www.)?([a-z0-9-]+).MYDOMAINNAME.com [NC] 
RewriteCond %{SCRIPT_FILENAME} !^/[COLOR="DarkRed"]MYDOMAINNAME[/COLOR]com [NC] 
RewriteRule ^(.*)$ /[COLOR="darkred"]MYDOMAINNAME[/COLOR]com/$1 [L]

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteCond %{REQUEST_URI} ^.*/wp-admin$
RewriteRule ^(.+)$ $1/ [R=301,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]

</IfModule>

<IfModule mod_security.c>
<Files async-upload.php>
SecFilterEngine Off
SecFilterScanPOST Off
</Files>
</IfModule>

Code (markup):

In the areas I highlighted in red . . . is " com " supposed to be after it there.

I am getting a " Internal Server Error 500 "

Thanks for your help !

 

Try this

RewriteRule dumps/(.*)\.html$ /download/dumps/showquestion.php?exam=$1 [QSA,L]

It works for me

 

sorry that looks like it is for a different script . . . this is the htaccess for WordPress MU