Even in SAIL v3.1 Build 109, the file /etc/shorewall/sark_rules is absent on an SME - it may be present in a pure CentOS install.
Possible PHP Syntax error in the file /opt/sark/generator/edsw.php at lines 23-26:
$file = '/etc/shorewall/sark_rules' or die('Could not read file!');
$change = false;
$handle = @fopen($file, "r");
which should be:
$file = '/etc/shorewall/sark_rules';
$change = false;
$handle = @fopen($file, "r") or die('Could not read file!');