You have an unusual problem. Every command runs as a little program and when a program produces a run time error, it is usually reported as a Segmentation fault. (Whether this terminology has a useful meaning, I don't know). On a normally configured machine, your command should not produce such an error. On FC3, "ls" is usually aliased to a longer command which gives a colorful display. Try:
and see if that "segfaults" too.
"Never let the task you are trying to accomplish distract you from the study of computers."