also tried with Seam2.x branch and ICEfaces current 1.7 branch ...all get following exception on this AS:-
2008-08-07 12:40:43,024 ERROR [org.jboss.seam.jsf.SeamPhaseListener] uncaught exception
java.lang.IllegalStateException: No active application scope
at org.jboss.seam.core.Init.instance(Init.java:78)
at org.jboss.seam.jsf.SeamPhaseListener.handleTransactionsBeforePhase(SeamPhaseListener.java:314)
at org.jboss.seam.jsf.SeamPhaseListener.beforeServletPhase(SeamPhaseListener.java:140)
at org.jboss.seam.jsf.SeamPhaseListener.beforePhase(SeamPhaseListener.java:114)
at com.sun.faces.lifecycle.Phase.handleBeforePhase(Phase.java:214)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:96)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at com.icesoft.faces.webapp.xmlhttp.PersistentFacesState.render(PersistentFacesState.java:189)
at com.icesoft.faces.webapp.xmlhttp.PersistentFacesState.executeAndRender(PersistentFacesState.java:373)
at com.icesoft.faces.webapp.xmlhttp.PersistentFacesState.setupAndExecuteAndRender(PersistentFacesState.java:394)
at com.icesoft.faces.webapp.http.core.UploadServer$ProgressCalculator.potentiallyNotify(UploadServer.java:189)
at com.icesoft.faces.webapp.http.core.UploadServer$ProgressCalculator.setListenerAndContextAndPFS(UploadServer.java:155)
at com.icesoft.faces.webapp.http.core.UploadServer$2.servlet(UploadServer.java:70)
at com.icesoft.faces.webapp.http.servlet.ServletRequestResponse.detectEnvironment(ServletRequestResponse.java:228)
at com.icesoft.faces.webapp.http.core.UploadServer.service(UploadServer.java:50)
at com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer$Matcher.serviceOnMatch(PathDispatcherServer.java:50)
at com.icesoft.faces.webapp.http.common.standard.PathDispatcherServer.service(PathDispatcherServer.java:19)
at com.icesoft.faces.webapp.http.servlet.ThreadBlockingAdaptingServlet.service(ThreadBlockingAdaptingServlet.java:19)
at com.icesoft.faces.webapp.http.servlet.EnvironmentAdaptingServlet.service(EnvironmentAdaptingServlet.java:63)
at com.icesoft.faces.webapp.http.servlet.MainSessionBoundServlet.service(MainSessionBoundServlet.java:164)
at com.icesoft.faces.webapp.http.servlet.SessionDispatcher.service(SessionDispatcher.java:41)
at com.icesoft.faces.webapp.http.servlet.PathDispatcher$Matcher.serviceOnMatch(PathDispatcher.java:52)
at com.icesoft.faces.webapp.http.servlet.PathDispatcher.service(PathDispatcher.java:29)
at com.icesoft.faces.webapp.http.servlet.MainServlet.service(MainServlet.java:90)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at com.icesoft.faces.webapp.xmlhttp.BlockingServlet.service(BlockingServlet.java:56)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
at org.jboss.seam.debug.hot.HotDeployFilter.doFilter(HotDeployFilter.java:68)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:80)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446)
at java.lang.Thread.run(Unknown Source)
2008-08-07 12:40:43,024 ERROR [org.jboss.seam.jsf.SeamPhaseListener] swallowing exception

Switched the jsf jars(1.2_09) on the embedded tomcat-6 for jboss-4.2.3.GA to those from jboss-4.2.2.GA (1.2_04), and everything worked fine, so problem is with the fileupload component and jsf1.2_09 on this AS.

I have tried both versions of jboss-4.2.3.GA available for download (the JDK5 and JDK6 versions) and problems exist with async execution. After PersistentFacesState.execute() the thread gets released and the seam contexts cannot be found for the render. Still looking at this, but wanted to comment on here that problem is not only with fileupload, but also with progressMonitor and ajax-push as well.

This appears to be fixed by the change for ICE-3532, however, file upload does not seem to be working with Safari.

Marking fixed as Safari 4.0 may be the source of the FileUpload problem there.