First of all you have to bypass the apache error by visiting yourwebsite.com/installation/?page=settings
Enter the details and continue. After installation edit lighttpd.conf and add following code:
url.rewrite-if-not-file = (
"^/action/([A-Za-z0-9_\-/]+)(?:\?(.*))?$" => "/system/handlers/actions.php?action=$1&$2",
"^/([A-Za-z0-9_\-]+)(?:\?(.*))?$" => "/index.php?h=$1&$2",
"^/([A-Za-z0-9_\-]+)/(.*)(?:\?(.*))?$" => "/index.php?h=$1&p=$2&$3"
)
Restart your lighttpd server and enjoy. The configuration above is tested on Ossn v3.x