GWT: com.google.gwt.core.client.JavaScriptException. only using Internet Explorer

Before explain my problem, I have to say that my GWT version is 2.2.0 and the error only has place when I use Internet Explorer (in this case IE 8).

I have a little GWT project which contains a button that throws the next method:

private void expotarExpediente(VistaExpediente vista) {
    final String templateURL = GWT.getHostPageBaseURL() + "exportar?id="
            + vista.getId();
    Window.open(
            templateURL,
            "Resultado de expotar el expediente: "
                    + vista.getNumeroExpediente(), "");
}

This method creates a template URL to call to a classic HTTPServlet ("exportar") which generates a Zip File to be downloaded by users. The sentence Window.open(...) open a window in the browser that allows download the file.

This works correctly in all browsers except Internet Explorer. The thrown exception is the next:

The thrown exception is the next

10:08:31.208 [ERROR] [sistemadefiniciontramites] Uncaught exception escaped com.google.gwt.core.client.JavaScriptException: (Error): Argumento no válido. number: -2147024809 description: Argumento no válido. at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:237) at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:129) at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269) at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91) at com.google.gwt.core.client.impl.Impl.apply(Impl.java) at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214) at sun.reflect.GeneratedMethodAccessor18.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157) at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281) at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531) at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352) at java.lang.Thread.run(Unknown Source)

I can´t find any decent solution searching by google. I would like to know if someone has had this problem or a similar problem before and if he or she could overcome it.

Thanks and excusme for my poor English.