If you are using the Cloudfront library for Amazon Advertising API and you get the following error message, contact me I can help you with this issue. I got this error when I tried to retrieve amazon.fr (france) data.
exception 'Exception' with message 'String could not be parsed as XML' in cloudfusion\sdk.class.php:1209
Stack trace:
#0 \sdk.class.php(1209): SimpleXMLElement->__construct('parse_callback('pas_authenticate('ItemLookup', Array)
#3 amazonProductAdvertisingApi.php(233): AmazonPAS->item_lookup('B000091xxx', Array)
#4 amazonProductAdvertisingApi.php(90): amazonProductAdvertisingApi->getAsinData()
#5 amazonProductAdvertisingApi.php(65): amazonProductAdvertisingApi->getResult('FR')
#6 \index.php(248): amazonProductAdvertisingApi->getResults()
#7 {main}EOL#0 cloudfusion\sdk.class.php(1209): SimpleXMLElement->__construct('parse_callback('pas_authenticate('ItemLookup', Array)
#3 amazonProductAdvertisingApi.php(233): AmazonPAS->item_lookup('B000091xxx', Array)
#4 amazonProductAdvertisingApi.php(90): amazonProductAdvertisingApi->getAsinData()
#5 amazonProductAdvertisingApi.php(65): amazonProductAdvertisingApi->getResult('FR')
#6 eansuche\index.php(248): amazonProductAdvertisingApi->getResults()
#7 {main}