Amazon API URL - element search invalid for this endpoint

Question

Thus, I had problems creating an API request for Amazon and returning an XML that displays product information, in particular price. I use a signed query helper to generate my queries and follow the examples in the AWS documentation.

here is my request url and parameters:

http://webservices.amazon.com/onca/xml? Service=AWSECommerceService &Operation=ItemLookup &ResponseGroup=OfferFull &Condition=All &IdType=ASIN &ItemId=B001L8NG0Q 

the helper also generates my signature, access keys, etc. However, this is what returns that I am sending this request:

  <ErrorResponse xmlns="http://ecs.amazonaws.com/doc/2005-10-05/"> <Error> <Code>InvalidAction</Code> <Message> The action ItemLookup is not valid for this endpoint. </Message> </Error> <RequestId>a006f1ec-11b3-4afd-a5a3-cb8cfd7e4186</RequestId> </ErrorResponse> 

Any ideas on what my problem is here? It seems I can make this work fine for keyword queries, but I am having problems viewing this item.