Wrong with this particular code?

require 'xmlrpc/client'
def find_product(key, upc)
  server = XMLRPC::Client.new2('http://www.upcdatabase.com/xmlrpc')
  begin
    response = server.call('lookup',[{'rpc_key' => key}, {'upc' =>upc}] )
    rescue XMLRPC::FaultException => e
    puts "Error: "
    puts e.faultCode
    puts e.faultString
  end
end
dev_key  = '40bf22cb32833a2af48fd65121128fc28e42d580'
upc_code = '099482409463'
puts find_product(dev_key, upc_code)

Response from UPCdatabase

{"status"=>"fail", "message"=>"Invalid parameters"}

I'm not in a position to discover, which parameter is invalid, as there's very little information on http://www.upcdatabase.com/ regarding their API.

Can anybody assist me to? I'm using Ruby 1.9.2

That's so funny which i only agreed to be banging my mind on a single factor. This code works best for me:

require 'xmlrpc/client'
server = XMLRPC::Client.new("www.upcdatabase.com", "/xmlrpc")
result = server.call("lookup", 'rpc_key' => "mykey", 'upc' => "071160055506")

Edit: I additionally found http://www.upcdatabase.org/api.php that has really a json api, I'll give that the try also and publish back if you'd like.