in reply to opendir in file find
On Linux it works like so:
I have the following structure x/y/z where z is a file and x and y are directories.
dr--r--r--: This allows listing x and seeing y but y cannot have stat called on it so nothing can be determined about it. y cannot be listed.
d--x--x--x: This allows y to be listed if you already know that it is there. x cannot be listed. You can chdir to x.
dr-xr-xr-x: x can be listed and chdir'ed to y is fully functional.
So I would say that for a directory to be useable from the standpoint of File::Find that read (-r) and execute (-x) will probably both be needed on a directory in question.