There is a known problem with launching the Java examples by executing run.bat or pjava/pjava_g commands. The application is starting too early and gets obscured by other application windows. You can shut applications by pressing Shift-Ctrl-Alt-K key combination in the emulator to get the Java application visible.
Possible reason to the error messages is missing or corrupted .txt file (contains pjava launching parameters). Also other installed JDK/JRE/Java SDK versions might affect on this.