Re: ange-ftp errors out for some directories

[Richard Stallman]

    It appears that, for some reason, dired-actual-switches fails to
    be set.

That is strange, because dired-mode should have set it.
I wonder if the wrong buffer is current.  Please type 
e (current-buffer) RET in the debugger and see.

If it is the right buffer, then the question is how
dired-actual-switches got to be nil.  Debugging that probably requires
examining its variables at various points in the execution sequence.
See if dired-mode does get called.  See if it sets
dired-actual-switches.  If yes, see if the value is correct there.  If
yes, see who sets it again later.