Sometimes the Unix window manager is too attentive and catches key events before they get to (X)Emacs, notably the `ALT arrow' keys. You either rebind those keys through customization, or you have to edit the resource file of the window manager to suppress this behavior. For example, if you use the fvwm window manager, then add/edit the following lines to/in your '.fvwmrc' file:
# press arrow + control anywhere, and scroll by 1 page
Key Left R C Scroll -100 0
Key Right R C Scroll +100 +0
Key Up R C Scroll +0 -100
Key Down R C Scroll +0 +100
# press arrow + meta key, and scroll by 1/10 of a page
Key Left R M Scroll -10 +0
Key Right R M Scroll +10 +0
Key Up R M Scroll +0 -10
Key Down R M Scroll +0 +10
A different problem occurs if your X11 system requires the specification of width and height as options to ghostscript. If the default size of the ghostscript window is wrong on your system, please add the option '-g550x720' to the gs-command configuration variable.