You may have a look at
this (step 4) to define the "XOOPS_TRUST_PATH".
Yes, there are 2 sets of files to be copied, one to XOOPS_ROOT_PATH/modules/, and one to XOOPS_TRUST_PATH/modules/
The two red lines should be added exactly as instructed in the README.
Here is an example of my mainfile.
define('XOOPS_ROOT_PATH', '/home/avtx30/public_html');
define('XOOPS_URL', 'http://www.nhatban.net');
define('XOOPS_TRUST_PATH','/home/avtx30/trusted');
// blah blah
include XOOPS_TRUST_PATH.'/modules/protector/include/precheck.inc.php' ;
if (!isset($xoopsOption['nocommon']) && XOOPS_ROOT_PATH != '') {
include XOOPS_ROOT_PATH."/include/common.php";
}
include XOOPS_TRUST_PATH.'/modules/protector/include/postcheck.inc.php' ;
HTH