Amazon Module Error -> Line 269 (reading the items)

In Administer > Site Configuration > Amazon API is the tab Test, to test if the module works with a valid ASIN or ISBN number.
ut if I use a valid ASIN then it just gives an error: warning: Invalid argument supplied for foreach() in /Applications/MAMP/htdocs/*****/modules/amazon/amazon.module on line 269. and then it just wont work. It wont display anything.

Line 269 is the line where it tries to read the xml response from Amazon, namely this line: foreach($results->Items->Item as $xml) {
I first tried communicating with Amazon without Drupal and that worked fine. The XML is also still structureds like Items->Item, so that's not the problem.

Anybody that has a solution for this problemn ?

The versions I'm using are:

drupal 6.3
amazon 6.x-1.0-beta3