OK I've tested the plugin and managed to fix the notices with the following changes:
qa-webmaster-layer.php line 5, change to
function __construct($template, $content, $rooturl, $request)
qa-webmaster-layer.php lines 462, 464, 466 change each of them to
$val = (int) $val * 1024;
library/security.php, line 16, change to:
$security['magic_quotes_gpc']['value'] = 0;
Hopefully that should be everything!