SLIME uses the Display PostScript extension to the X Window System for the model editor display. If the main window does not appear or appears and immediately disappears and you see the message
SLIME1: CAN NOT CREATE RENDERING CONTEXT FOR EDITOR --- QUITTING SLIME1: This may indicate that your display is not capable of SLIME1: handling Display PostScript. Check that you are running SLIME1: the correct X server.then it is likely you are not running an X server that is capable of handling Display PostScript requests (this message can also appear if the server has run out of a certain class of resources but this is extremely unlikely). You should shut down the X Window System and restart it with a server that supports Display PostScript. Servers from the X Consortium sample distribution do not support the Display PostScript extension, which is a commercial product, but most vendor-supplied servers do. For example the OpenWindows server and the AIXwindows server both support Display PostScript.
There are a few systems for which Display PostScript is not available (eg. Linux). You can not run SLIME on these systems.
If you are not sure how to change your X server or which server you should use on your system, you should consult a local expert.