Problem with currency XAU/USD and UKOil

Hi, I would like to ask what shoud I do when I want to get a XAU/USD UKOil from JavaFixHistoryMiner API? When I set a parameter to XAU/USD or UKOil I have a error:
java.lang.NullPointerException
at com.fxcm.fix.pretrade.MarketDataRequest.toMessage(MarketDataRequest.java:760)
Displaying history in
5...
at com.fxcm.fix.pretrade.MarketDataRequest.toMessage(MarketDataRequest.java:612)
at com.fxcm.internal.transport.FXCMGateway.sendMessage(FXCMGateway.java:782)
at MyPackage.JavaFixHistoryMiner.sendRequest(JavaFixHistoryMiner.java:226)
at MyPackage.JavaFixHistoryMiner.messageArrived(JavaFixHistoryMiner.java:358)
at MyPackage.JavaFixHistoryMiner.messageArrived(JavaFixHistoryMiner.java:279)
at com.fxcm.internal.transport.FXCMGateway.update(FXCMGateway.java:903)
at com.fxcm.messaging.util.fix.FIXUserSession$BackToUserQueue.run(FIXUserSession.java:709)

When I get e.g a EUR/USD I don't have a problem.
Please, help me.