When I visit my web application on newly installed Tomcat 7, a message shows up: SEVERE : org . zkoss . zk . ui . UiException : javax . imageio . IIOException : Can 't create output str eam! at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct orAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC onstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) ... at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpo int.java:2442) at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoin t.java:2431) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec utor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor .java:908) at org.apache.tomcat.util.t...