$uri = "http://webservices.amazon.co.jp/onca/xml?" .
"Service=AWSECommerceService" .
"&Operation=BrowseNodeLookup" .
"&MerchantId=All" .
"&Condition=All" .
"&Sort=salesrank" .
"&Version=$this->version" .
"&AssociateTag=$this->associateTag" .
"&SearchIndex=Books" .
"&BrowseNodeId=465610" .
"&ResponseGroup=TopSellers";
Try that, you don't need the BrowseNode, it will only limit the records you get to the browsenode 17 which is Literature & Fiction, and that is on US, not on jp, I don't know if it's different in jp.