Cannot access Product Advertising API on EC2 instance

I deployed a micro EC2 Windows instance and I'm trying to get through to the Amazon Product Advertising API. Is there a difference url if I am on a EC2 instance? The same url's work on my pc outside the ec2 network. I have an internet connection and can access http://ecs.amazonaws.com

[ERROR] 2011-08-09 17:36:41,956 could not retrieve batch
java.io.IOException: Server returned HTTP response code: 400 for URL: http://ecs.amazonaws.com/onca/xml?AWSAccessKeyId=[key]&Condition=New&IdType=UPC&IncludeReviewsSummary=False&ItemId=[parameters]&Service=AWSECommerceService&Timestamp=2011-08-09T16%3A36%3A41Z&Version=2010-11-01&Signature=c8MBHhPCa3BF96YTl8xEbYnw0YQvt2wsYAU%2BWl0apFw%3D
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
    at com.sun.org.apache.xerces.internal.impl.XMLVersionDetector.determineDocVersion(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source)
    at javax.xml.parsers.DocumentBuilder.parse(Unknown Source)
    at 
    at java.lang.Th开发者_如何学JAVAread.run(Unknown Source)