Two Drush bam-backup errors: Command not Found & Could not find a Drupal setting.php file at
Where is the settings.php file for your Drupal installation?

The problem Drush is having is that it cannot figure out where your settings.php file is.  By default, Drush only looks in sites/default.  There are a few ways that you can select the site you want if it is not in sites/default.  One is to cd to the directory that contains the settings.php file, then run your command.

cd /path/to/drupal/sites/mysite
drush status


The other way is to specify the site you mean via the --uri parameter:

drush --root=/path/to/drupal --uri=mysite.com status


Once the status command works per the above advice, try calling bam-backup again.