I there
i have this domain.com ponted to /home/username/public_html/domain.com
domain.com
/home/username/public_html/domain.com
I added this lines to the .htaccess
An internal server error has often something to do with Apache and /var/log/httpd/ is the error log file of apache, so I think you are in the right file.
The error path is set in php.ini. To get the path use ini_get():