HTTP ERROR 500

Problem accessing /return. Reason:

    java.lang.Double cannot be cast to java.lang.Long
Caused by:

java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Long
	at net.asteasolutions.imagenation.server.paypal.servlets.ExpressCheckoutSuccessHandler.generateNewOrderID(ExpressCheckoutSuccessHandler.java:180)
	at net.asteasolutions.imagenation.server.paypal.servlets.ExpressCheckoutSuccessHandler.generateOrderAndItemIDsForOrder(ExpressCheckoutSuccessHandler.java:86)
	at net.asteasolutions.imagenation.server.paypal.servlets.ExpressCheckoutSuccessHandler.doGet(ExpressCheckoutSuccessHandler.java:68)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:735)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:530)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:426)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:931)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:361)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:867)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:47)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:113)
	at org.eclipse.jetty.server.Server.handle(Server.java:337)
	at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:581)
	at org.eclipse.jetty.server.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:1005)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:560)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:222)
	at org.eclipse.jetty.server.HttpConnection.handle(HttpConnection.java:417)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:474)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:437)
	at java.lang.Thread.run(Thread.java:679)
Powered by Jetty://