In GNU Emacs 22.1.50.8 (i686-pc-linux-gnu, GTK+ Version 2.10.11)
 of 2007-08-21 on trpaslik
Windowing system distributor `The X.Org Foundation', version 11.0.70200000
configured using `configure  '--with-gtk' '--prefix' '/usr/local'
'--with-xpm' '--with-jpeg' '--with-png' '--with-gif''

Visit some FTP site:

  "C-x d /anonymous@ftp.gnu.org:/ RET"

Then try running a shell:

  "M-x shell RET"

I see a backtrace:

Debugger entered--Lisp error: (wrong-type-argument processp nil)
  process-coding-system(nil)
  comint-exec-1("shell" #<buffer *shell*> "/bin/bash" ("--noediting" "-i"))
  comint-exec(#<buffer *shell*> "shell" "/bin/bash" nil ("--noediting"
"-i"))
  make-comint-in-buffer("shell" #<buffer *shell*> "/bin/bash" nil
"--noediting" "-i")
  apply(make-comint-in-buffer "shell" #<buffer *shell*> "/bin/bash" nil
("--noediting" "-i"))
  shell(nil)
  call-interactively(shell)
  execute-extended-command(nil)
  call-interactively(execute-extended-command)


I think I may have seen and reported this before - it does look familiar.