Thought I'd post my success in fixing the blank page issue I was having. Hopefully, it can help others. After much hair pulling, I realized that the modules/fedexwebservices.php file was looking for both the catalog location and the includes location (lines 60 - 74):
//Class Methods
function quote($method = '') {
/* FedEx integration starts */
global $shipping_weight, $shipping_num_boxes, $cart, $order;
require_once(DIR_FS_CATALOG . DIR_WS_INCLUDES . 'library/fedex-common.php5');
//if (MODULE_SHIPPING_FEDEX_WEB_SERVICES_SERVER == 'test') {
//$request['Version'] = array('ServiceId' =&--#62; 'crs', 'Major' =&--#62; '7', 'Intermediate' =&--#62; '0', 'Minor' =&--#62; '0');
//$path_to_wsdl = DIR_WS_INCLUDES . "wsdl/RateService_v7_test.wsdl";
//} else {
$path_to_wsdl = DIR_FS_CATALOG . DIR_WS_INCLUDES . "wsdl/RateService_v9.wsdl";
//}
ini_set("soap.wsdl_cache_enabled", "0");
$client = new SoapClient($path_to_wsdl, array('trace' =&--#62; 1));
It wasn't throwing any errors within the server error logs and was extremely frustrating to snoop out. The following update to the code finally resolved the issue.
//Class Methods
function quote($method = '') {
/* FedEx integration starts */
global $shipping_weight, $shipping_num_boxes, $cart, $order;
require_once(DIR_WS_INCLUDES . 'library/fedex-common.php5');
$path_to_wsdl = DIR_WS_INCLUDES . 'wsdl/RateService_v9.wsdl';
ini_set("soap.wsdl_cache_enabled", "0");
$client = new SoapClient($path_to_wsdl, array('trace' =&--#62; 1));