error message while using TAB for auto completion

[Venkatesh Pitta]

I started dired, backspaced all the characters that come up for the
pwd, then typed in /, m, e, pressed TAB key for auto completion.  That
gave me this backtrace.

Debugger entered--Lisp error: (wrong-number-of-arguments (lambda
(filename directory) "Like `file-name-completion' for tramp files."
(try-completion filename (mapcar (quote list)
(file-name-all-completions filename directory)))) 3)
  tramp-completion-handle-file-name-completion("me" "/" file-exists-p)
  apply(tramp-completion-handle-file-name-completion ("me" "/" file-exists-p))
  (progn (apply (cdr fn) args))
  (unwind-protect (progn (apply ... args)) (set-match-data
save-match-data-internal (quote evaporate)))
  (let ((save-match-data-internal ...)) (unwind-protect (progn ...)
(set-match-data save-match-data-internal ...)))
  (save-match-data (apply (cdr fn) args))
  (if fn (save-match-data (apply ... args))
(tramp-completion-run-real-handler operation args))
  (let ((fn ...)) (if fn (save-match-data ...)
(tramp-completion-run-real-handler operation args)))
  tramp-completion-file-name-handler(file-name-completion "me" "/"
file-exists-p)
  read-file-name-internal("~//me" "~/" nil)
  minibuffer-complete()
  call-interactively(minibuffer-complete)
  read-file-name("Dired (directory): " nil "/home/santhi/" nil)
  dired-read-dir-and-switches("")
  call-interactively(dired)

Emacs version: 22.1.1.
tramp version: 2.1.5
OS: Debian Lenny

the lines referring to tramp in my .emacs are:
(require 'tramp)
(setq tramp-default-method "scpx")

Interestingly, M-x apt-utils-show-package RET tramp says tramp is _not
installed_ since it clearly depends on emacs21 | xemacs21.  But I am
using emacs22 that is available with Debian Lenny and not getting any
error.

The following code (got from #emacs) stops the error message and gets
the TAB key working as usual (as it was in emacs21.4).
(progn (require 'tramp) (setq file-name-handler-alist (loop for x
            in file-name-handler-alist for (pattern . symbol) = x for name =
            (symbol-name symbol) unless (string-match "tramp" name) collect
            x)))

Thought this could be a bug.  Or just something wrong with my .emacs?

regards,
Venkatesh