getting Internal Error for trying to refund

[ohadperry]

Hi, I have used this like so:

pp = PaypalAdaptive::Request.new("staging")

refund_data =  {
          receiverList:           {receiver: [amount:50]},
          requestEnvelope:        {errorLanguage: 'en_US', detailLevel: 'ReturnAll'},
          currencyCode:           'USD',
          transactionId:          "3LB17176J1579470G"
      }

pp.refund(refund_data)

the result is:

{"responseEnvelope"=>{"timestamp"=>"2014-01-29T04:43:15.462-08:00", 
"ack"=>"Failure", "correlationId"=>"64008dca7cba5", "build"=>"7935900"}, 
"error"=>[{"errorId"=>"520002", "domain"=>"PLATFORM",
 "subdomain"=>"Application", "severity"=>"Error", 
"category"=>"Application", "message"=>"Internal Error"}]}