SmartFAQ is developed by The SmartFactory (https://www.smartfactory.ca), a division of InBox Solutions (https://www.inboxsolutions.net)
"Warning: copy(../mainfile.php): failed to open stream: Permission denied
Likely you don't have access to your mainfile.php on your server. Contact your host and ask them to make it writeable until after your install finishes.
You can easily change passwords in the database in case you lost them. You can even let phpmyadmin convert them into the md5 format in which they are stored.