Re-setting up working project on local machine - php

Question

I'm working on a symfony 1.4 project which is working, i wanted to work on a local copy on my personal machine; so I've settled a virtual host (I'm on a Windows 8.1 with xamppp web server).
I'm getting a 500 error when trying to access from browser by giving "joyaa" (it's the virtualhost alias), and in some of my test I had a redirect to the project working on the server (it's a statement in .htaccess)
This is the virtual host defining:
<VirtualHost *:80>
ServerName joyaa
DocumentRoot "C:/xampp/htdocs/yaol/web"
DirectoryIndex index.php
<Directory "C:/xampp/htdocs/yaol/web">
AllowOverride All
Allow from All
</Directory>
Alias /sf C:/xampp/htdocs/yaol/lib/vendor/symfony/data/web/sf
<Directory "C:/xampp/htdocs/yaol/lib/vendor/symfony/data/web/sf">
AllowOverride All
Allow from All
</Directory>
Alias /joyaa "C:/xampp/htdocs/yaol/web"
<Directory "C:/xampp/htdocs/yaol/">
Options Indexes FollowSymLinks
AllowOverride All
Order allow,deny
Allow from all
</Directory>
</VirtualHost>
and this is the .htaccess defining:
Options +FollowSymLinks +ExecCGI
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /joyaa
RewriteRule ^yaol(.*)$ http://www.arcadja.com/joyaa$1 [L,R=301]
# we check if the .html version is here (caching)
RewriteRule ^$ index.html [QSA]
RewriteRule ^([^.]+)$ $1.html [QSA]
RewriteCond %{REQUEST_FILENAME} !-f
# no, so we redirect to our front web controller
RewriteRule ^(.*)$ index.php [QSA,L]
</IfModule>
Probably it's a configuration problem but I'm not sure about where to look at... Please help. Thanks