ispCP - Board - Support - VHCS fork

Hi all
Hi have found some site that tell how to speed up caching using the htaccess file for caching management.
I would like to set a future expire heater for some files like this:

<FilesMatch "\.(ico|gif|js|css)$">
Header set Expires "Thu, 15 Apr 2010 20:00:00 GMT"
</FilesMatch>

But when I activate the .htaccess the server answer error 500.

Where is the problem?

I found myself
There is to move some modules from dir availavle to dir enabled.

Better : a2enmod [modul-name]
or make a logical Link