Error on re-using the URL of export RDF in turtle format

[Busa78]

I experience this problem when I try to access the export RDF link.

What steps will reproduce the problem?

1. Export a project using "Export RDF as Turtle" (es. http://127.0.0.1:3333/command/core/export-rows/Bankadati-BDC-Portafoglio-Servizi.ttl) -->OK
2. Copy the url and try to re download the same ttl file (i.e. open in another tab the same URL) give me the error.

The Error
HTTP ERROR 500

Problem accessing /command/core/export-rows/Bankadati-BDC-Vendita.ttl. Reason:

INTERNAL_SERVER_ERROR

Caused by:
java.lang.UnsupportedOperationException
at com.google.refine.commands.Command.doGet(Command.java:86)
at com.google.refine.RefineServlet.service(RefineServlet.java:170)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at org.mortbay.servlet.UserAgentFilter.doFilter(UserAgentFilter.java:81)
at org.mortbay.servlet.GzipFilter.doFilter(GzipFilter.java:132)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.jetty.bio.SocketConnector$Connection.run(SocketConnector.java:228)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

What version of Google Refine are you using?
Google Refine 2.5 [r2407]

What operating system and browser are you using?
Win 7 32 bit; Google Chrome Version 27.0.1453.94 m

Did you resolved the problem or have any Idea of the strange behavior?

Google Refine version?

• Google Refine 2.5 [r2407]

RDF -Extension version?

• grefine-rdf-extension-0.8.0
  What operating system and browser are you using?
  Win 7 32 bit; Google Chrome Version 27.0.1453.94 m

Did you have any Idea about this error?