Server Side Includes don't work
 

I've activated ssi for the site, saved rechecked it, even rebooted it, but can't get them to work.

I've tried different variations of this line:

<!--#include virtual="/_menu.html" -->

including using the full domain. Am I making a mistake in it or is there somthing more I have to do to get ssi working with ISPconfig?

Is the apache module "mod_include" installed and activated in your apache server?

Is there an easy way to check?

Take a look at your Apache configuration.
Which distribution do you use?

I don't know.

I just ordered a hetzner server in December with debian 4.0 min and hired you guys to set it up with ISPconfig.

Then your distribution is Debian 4.0. ;)
What's the output of and ?

-rw-r--r-- 1 root root 66 Dec 11 22:50 actions.load
-rw-r--r-- 1 root root 62 Dec 11 22:50 alias.load
-rw-r--r-- 1 root root 60 Dec 11 22:50 asis.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 auth_basic.load
-rw-r--r-- 1 root root 74 Dec 11 22:50 auth_digest.load
-rw-r--r-- 1 root root 74 Dec 11 22:50 authn_alias.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 authn_anon.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 authn_dbd.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 authn_dbm.load
-rw-r--r-- 1 root root 78 Dec 11 22:50 authn_default.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 authn_file.load
-rw-r--r-- 1 root root 90 Dec 11 22:50 authnz_ldap.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 authz_dbm.load
-rw-r--r-- 1 root root 78 Dec 11 22:50 authz_default.load
-rw-r--r-- 1 root root 82 Dec 11 22:50 authz_groupfile.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 authz_host.load
-rw-r--r-- 1 root root 74 Dec 11 22:50 authz_owner.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 authz_user.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 autoindex.load
-rw-r--r-- 1 root root 62 Dec 11 22:50 cache.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 cern_meta.load
-rw-r--r-- 1 root root 58 Dec 11 22:50 cgi.load
-rw-r--r-- 1 root root 68 Dec 11 22:50 cgid.conf
-rw-r--r-- 1 root root 60 Dec 11 22:50 cgid.load
-rw-r--r-- 1 root root 76 Dec 11 22:50 charset_lite.load
-rw-r--r-- 1 root root 58 Dec 11 22:50 dav.load
-rw-r--r-- 1 root root 36 Dec 11 22:50 dav_fs.conf
-rw-r--r-- 1 root root 79 Dec 11 22:50 dav_fs.load
-rw-r--r-- 1 root root 68 Dec 11 22:50 dav_lock.load
-rw-r--r-- 1 root root 58 Dec 11 22:50 dbd.load
-rw-r--r-- 1 root root 107 Dec 11 22:50 deflate.conf
-rw-r--r-- 1 root root 66 Dec 11 22:50 deflate.load
-rw-r--r-- 1 root root 145 Jan 16 12:34 dir.conf
-rw-r--r-- 1 root root 58 Dec 11 22:50 dir.load
-rw-r--r-- 1 root root 169 Dec 11 22:50 disk_cache.conf
-rw-r--r-- 1 root root 89 Dec 11 22:50 disk_cache.load
-rw-r--r-- 1 root root 64 Dec 11 22:50 dump_io.load
-rw-r--r-- 1 root root 58 Dec 11 22:50 env.load
-rw-r--r-- 1 root root 66 Dec 11 22:50 expires.load
-rw-r--r-- 1 root root 72 Dec 11 22:50 ext_filter.load
-rw-r--r-- 1 root root 89 Dec 11 22:50 file_cache.load
-rw-r--r-- 1 root root 64 Dec 11 22:50 filter.load
-rw-r--r-- 1 root root 66 Dec 11 22:50 headers.load
-rw-r--r-- 1 root root 62 Dec 11 22:50 ident.load
-rw-r--r-- 1 root root 68 Dec 11 22:50 imagemap.load
-rw-r--r-- 1 root root 66 Dec 11 22:50 include.load
-rw-r--r-- 1 root root 60 Dec 11 22:50 info.load
-rw-r--r-- 1 root root 60 Dec 11 22:50 ldap.load
-rw-r--r-- 1 root root 76 Dec 11 22:50 log_forensic.load
-rw-r--r-- 1 root root 185 Dec 11 22:50 mem_cache.conf
-rw-r--r-- 1 root root 87 Dec 11 22:50 mem_cache.load
-rw-r--r-- 1 root root 60 Dec 11 22:50 mime.load
-rw-r--r-- 1 root root 89 Dec 11 22:50 mime_magic.conf
-rw-r--r-- 1 root root 72 Dec 11 22:50 mime_magic.load
-rw-r--r-- 1 root root 74 Dec 11 22:50 negotiation.load
-rw-r--r-- 1 root root 66 Dec 23 18:38 perl.conf
-rw-r--r-- 1 root root 60 Dec 23 18:38 perl.load
-rw-r--r-- 1 root root 135 Jan 16 12:38 php5.conf
-rw-r--r-- 1 root root 59 Dec 17 21:04 php5.load
-rw-r--r-- 1 root root 589 Dec 11 22:50 proxy.conf
-rw-r--r-- 1 root root 62 Dec 11 22:50 proxy.load
-rw-r--r-- 1 root root 87 Dec 11 22:50 proxy_ajp.load
-rw-r--r-- 1 root root 103 Dec 11 22:50 proxy_balancer.load
-rw-r--r-- 1 root root 95 Dec 11 22:50 proxy_connect.load
-rw-r--r-- 1 root root 87 Dec 11 22:50 proxy_ftp.load
-rw-r--r-- 1 root root 89 Dec 11 22:50 proxy_http.load
-rw-r--r-- 1 root root 66 Dec 11 22:50 rewrite.load
-rw-r--r-- 1 root root 68 Dec 11 22:50 setenvif.load
-rw-r--r-- 1 root root 298 Dec 11 22:50 sick-hack-to-update-modules
-rw-r--r-- 1 root root 66 Dec 11 22:50 speling.load
-rw-r--r-- 1 root root 1781 Dec 11 22:50 ssl.conf
-rw-r--r-- 1 root root 58 Dec 11 22:50 ssl.load
-rw-r--r-- 1 root root 64 Dec 11 22:50 status.load
-rw-r--r-- 1 root root 64 Dec 11 22:50 suexec.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 unique_id.load
-rw-r--r-- 1 root root 293 Dec 11 22:50 userdir.conf
-rw-r--r-- 1 root root 66 Dec 11 22:50 userdir.load
-rw-r--r-- 1 root root 70 Dec 11 22:50 usertrack.load
-rw-r--r-- 1 root root 66 Dec 11 22:50 version.load
-rw-r--r-- 1 root root 74 Dec 11 22:50 vhost_alias.load
srv1:/# ls -la /etc/apache2/mods-enabled
total 8
drwxr-xr-x 2 root root 4096 Jan 16 12:39 .
drwxr-xr-x 8 root root 4096 Jan 16 13:03 ..
lrwxrwxrwx 1 root root 28 Jan 16 12:21 alias.load -> ../mods-available/alias.load
lrwxrwxrwx 1 root root 33 Jan 16 12:21 auth_basic.load -> ../mods-available/auth_basic.load
lrwxrwxrwx 1 root root 33 Jan 16 12:21 authn_file.load -> ../mods-available/authn_file.load
lrwxrwxrwx 1 root root 36 Jan 16 12:21 authz_default.load -> ../mods-available/authz_default.load
lrwxrwxrwx 1 root root 38 Jan 16 12:21 authz_groupfile.load -> ../mods-available/authz_groupfile.load
lrwxrwxrwx 1 root root 33 Jan 16 12:21 authz_host.load -> ../mods-available/authz_host.load
lrwxrwxrwx 1 root root 33 Jan 16 12:21 authz_user.load -> ../mods-available/authz_user.load
lrwxrwxrwx 1 root root 32 Jan 16 12:21 autoindex.load -> ../mods-available/autoindex.load
lrwxrwxrwx 1 root root 26 Jan 16 12:23 cgi.load -> ../mods-available/cgi.load
lrwxrwxrwx 1 root root 26 Jan 16 12:21 dir.conf -> ../mods-available/dir.conf
lrwxrwxrwx 1 root root 26 Jan 16 12:21 dir.load -> ../mods-available/dir.load
lrwxrwxrwx 1 root root 26 Jan 16 12:21 env.load -> ../mods-available/env.load
lrwxrwxrwx 1 root root 30 Jan 16 12:39 include.load -> ../mods-available/include.load
lrwxrwxrwx 1 root root 27 Jan 16 12:21 mime.load -> ../mods-available/mime.load
lrwxrwxrwx 1 root root 34 Jan 16 12:21 negotiation.load -> ../mods-available/negotiation.load
lrwxrwxrwx 1 root root 27 Jan 16 12:23 perl.conf -> ../mods-available/perl.conf
lrwxrwxrwx 1 root root 27 Jan 16 12:23 perl.load -> ../mods-available/perl.load
lrwxrwxrwx 1 root root 27 Jan 16 12:23 php5.conf -> ../mods-available/php5.conf
lrwxrwxrwx 1 root root 27 Jan 16 12:23 php5.load -> ../mods-available/php5.load
lrwxrwxrwx 1 root root 30 Jan 16 12:39 rewrite.load -> ../mods-available/rewrite.load
lrwxrwxrwx 1 root root 31 Jan 16 12:21 setenvif.load -> ../mods-available/setenvif.load
lrwxrwxrwx 1 root root 26 Jan 16 12:39 ssl.conf -> ../mods-available/ssl.conf
lrwxrwxrwx 1 root root 26 Jan 16 12:39 ssl.load -> ../mods-available/ssl.load
lrwxrwxrwx 1 root root 29 Jan 16 12:21 status.load -> ../mods-available/status.load
lrwxrwxrwx 1 root root 29 Jan 16 12:39 suexec.load -> ../mods-available/suexec.load

mod_include is enabled, so that's not the problem. But make sure that module is allowed in the directory where your SSI files are:

( http://httpd.apache.org/docs/2.0/howto/ssi.html )