title: Amazon Product API ItemLook is returning invalid ItemID even though it is valid
body: <p>When calling ItemLookup to for ASIN <a href="https://rads.stackoverflow.com/amzn/click/com/B00281Z86A" rel="noreferrer" rel="nofollow noreferrer">B00281Z86A</a>, I am getting an error </p>
  
  <pre><code> B00281Z86A is not a valid value for ItemId. Please change this value and retry your request.
  </code></pre>
  
  <p>More complete</p>
  
  <pre>   
    {"Request":{"IsValid":"True","ItemLookupRequest":{"IdType":"ASIN","ItemId":"B00281Z86A","ResponseGroup":"Medium","VariationPage":"All"},"Errors":{"Error":{"Code":"AWS.InvalidParameterValue","Message":"B00281Z86A is not a valid value for ItemId. Please change this value and retry your request."}
  </pre>
  
  <p>This is a valid Amazon item as you can see here <a href="https://rads.stackoverflow.com/amzn/click/com/B00281Z86A" rel="noreferrer" rel="nofollow noreferrer">http://www.amazon.com/dp/B00281Z86A</a></p>