You MUST exit from A/UX Finder environment to launch X11.
One flexible way to do this is as follows:
1. Change Session Type to "Console Emulator"
2. Within Console Emulator window, you may execute the command below to get into A/UX Finder environment:
# mac32; screenrestore
3. When you want to execute X11, you choose "Logout" from the "Special" menu. It will bring you to the Console Emulator mode.
4. Within the Console Emulator mode, you may type "X11" to get into the X11 Window Systems environment. To get out of the X11 Window environment, type "exit" from the X Console window. This brings you back to the Console Emulator.