i know that this issue has been posted countless times however none of the answer that I have found seemed to solve my problem.

Here is my .htaccess:
### SILVERSTRIPE START ###
DirectorySlash Off
<Files *.ss>
Order deny,allow
Deny from all
Allow from 127.0.0.1
Allow from 212.113.133.130
</Files>

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase onedoor

RewriteCond %{REQUEST_URI} !(\.gif$)|(\.jpg$)|(\.png$)|(\.css$)|(\.js$)

RewriteCond %{REQUEST_URI} ^(.*)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* sapphire/main.php?url=%1&%{QUERY_STRING} [L]
</IfModule>
### SILVERSTRIPE END ###

For the RewriteBase writing onedoor or onedoor/ will result in raising the 500 error.
Then anything else will cause an error like : "cannot find some directory tried/sapphire/main.php on the server".
I have been trying to work this out for days now and I feel like I really need help on this issue.

I will appreciate any suggestion or help!!

Oh and whne i try to get the error.log of the server, there is nothing in it.

if try /onedoor i get this answer: "/onedoor/sapphire/main.php was not found on this server"

Yes that is correct! But each time I use RewriteBase /onedoor it says "The URL /onedoor/sapphire/main.php was not found on this server"

No I got the same internal server error!!