Please read https://www.opensource-socialnetwork.org/wiki/view/1101/how-to-report-a-bug-error-issue
Case A
use ossninfo.php?test=mod_rewrite
and provide the result

Verify that the Rewrite Module is installed onto the server. if hosted, check the docs..., if local, look in the apache directory(ies) for the the modules directory, and in it look for the rewrite module.
Because, if I am not mistaken, it's saying that the module's not there so that the rewrite is failing. The <If Module mod_rewrite.c> is the check to see if the module is installed, and if so, the contained code gets executed by the server. If either the code or module is missing, you'll get an error message.

The how-to link that Arsalan commented shows how to set things up on a linux machine, and what to look for.

@michieal, it has created the .htaccess in the main directory, but no matter what i do i keep getting a X MODREWRITE REQUIRED, my mod rewrite section looks like
IfModule modrewrite.c>

SetEnv HTTPMODREWRITE 1

RewriteEngine on

RewriteRule ^rewrite.php$ installation/tests/apache_rewrite.php [L]

RewriteRule ^action\/([A-Za-z0-9\\-\/]+)$ system/handlers/actions.php?action=$1&%{QUERYSTRING} [L]

RewriteCond %{REQUESTFILENAME} !-d
RewriteCond %{REQUESTFILENAME} !-f
RewriteRule ^([A-Za-z0-9\_\-]+)$ index.php?h=$1 [QSA,L]

RewriteCond %{REQUESTFILENAME} !-d
RewriteCond %{REQUESTFILENAME} !-f
RewriteRule ^([A-Za-z0-9\_\-]+)\/(.*)$ index.php?h=$1&p=$2 [QSA,L]

</IfModule>

OSSN writes own .htaccess to check if the directories are ok . You can see https://www.opensource-socialnetwork.org/wiki/view/3994/how-to-install-ossn-on-ubuntu-1804-2004-x64-using-command-line

First, the file has to be named: .htaccess
If it is not, Apache won't even read it. Apache being the webserver.

Here's the mod_rewrite section from my .htaccess file in the main directory of my webserver.

<IfModule mod_rewrite.c>
#SetEnv HTTP_MOD_REWRITE 1

RewriteEngine on

RewriteRule ^rewrite.php$ installation/tests/apache_rewrite.php [L]

RewriteRule ^action\/([A-Za-z0-9\_\-\/]+)$ system/handlers/actions.php?action=$1&%{QUERY_STRING} [L]

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([A-Za-z0-9\_\-]+)$ index.php?h=$1 [QSA,L]

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([A-Za-z0-9\_\-]+)\/(.*)$ index.php?h=$1&p=$2 [QSA,L]

</IfModule>

IF you do the installation steps, the ossn system will create the .htaccess file for you.
You can also use MOD_REWRITE to force the web address to https or to say, www.mywebsite.com instead of just mywebsite.com. But, that is beyond the scope of things here. Although, most good hosting companies will have instructions in their site's help files telling you exactly how to do that.