What could possibly cause a Linux "ls" command to return a seg fault?

view story

http://stackoverflow.com – I am installing some new software. It contains several libraries in a "Lib" directory. If I ls Lib from another directory, I get the usual list of files. I can issue dir and file commands and get reasonable results too. I can even copy files out of this directory to other directories. But if I cd to "Lib", it appears that any linux command I give returns a seg fault. I can't run ls, file, or dir in that directory. I can't even run date there without a seg fault. Much obliged if anyone can help me clear up this mystery. (HowTos)