android exception at receiving proper response from xmlrpc call from android to magento

I have successfully connected the my android app to magento server via xmlrpc api. Also I have successfully retrieved the 'catalogcategory.tree' using the xmlrpc api . Now I want to retrieve the product images from their 'product ids' , hence following is the code I have written in android

    Map map = new HashMap();
        map.put("product_id", 12446);
        map.put("product_id", 12445);
        Object[] productdetails1=new Object [] {map};
        Object medialist = null;
        Object param1[]=new Object[]{productdetails1};
        Object param[]=new Object[]{CS_CONSTANTS.session_id,"catalog_product_attribute_media.list",param1};
        try {
        medialist=client.callEx("call", param);
       Log.i("Out Put of Adding", medialist.toString());
    } catch (Exception e) {
       e.printStackTrace();

    } 
    Log.e("HERE","is array : " + String.valueOf(medialist.getClass().isArray())+"\n"
    +"class    : " + medialist.getClass().toString()+"\n"
    +"hashCode : " + String.valueOf(medialist.hashCode()));

Following is exception

 //12-27 15:11:04.936: W/System.err(22977): com.cs.xmlrpc.libraries.XMLRPCFault: XMLRPC Fault: Product not exists. [code 101]
 //12-27 15:11:04.936: W/System.err(22977): at com.cs.xmlrpc.libraries.XMLRPCClient.callEx(XMLRPCClient.java:226)

Following is the corresponding SOAPV1 code which runs OK on server

$client = new SoapClient('http://magentohost/api/soap/?wsdl');
$session = $client->login('apiUser', 'apiKey');
$result = $client->call($session, 'catalog_product_attribute_media.list', '12446');
var_dump($result);

I have cross checked the input product ids , they are all valid and exist on my magento server