403 forbiden error after migrating from apache
 

what should be file permissions for PHP files in vhost document root to enable
LSWS to process them. ( even chmod 777 does not help ) ?
Thanks in advance !

"0755" should be enough. Please make sure permissions for all directories along the path should be set properly, not just the document root.
The user that lshttpd is running as should has read permission on files served by LSWS.
Another choice is to reinstall LSWS, set user to that of Apache.