ange-ftp error: ange-ftp-hash-entry-exists-p: Wrong type argument: hash-table-p, nil

ange-ftp error: ange-ftp-hash-entry-exists-p: Wrong type argument: hash-table-p, nil

[John Owens]

I am explicitly instructing tramp to use ange-ftp for an editing
session. It connects properly but then fails as follows:

Opening FTP connection to IPADDRESS...done
Logging in as user username@IPADDRESS...done
Getting PWD...done
Doing CD...done
Listing /username@IPADDRESS:/...done
ange-ftp-hash-entry-exists-p: Wrong type argument: hash-table-p, nil
Quit

Debug follows. I am using the straight-out-of-CVS emacs version from 7
Nov 2003 on OS X 10.3.1 ("GNU Emacs 21.3.50.1
(powerpc-apple-darwin7.0.0) of 2003-11-07").

Suggestions?

JDO

Debugger entered--Lisp error: (wrong-type-argument hash-table-p nil)
  gethash("." nil unknown)
  ange-ftp-hash-entry-exists-p("." nil)
  ange-ftp-file-attributes("/username@IPADDRESS:/")
  apply(ange-ftp-file-attributes "/username@IPADDRESS:/")
  ange-ftp-hook-function(file-attributes
"/username@IPADDRESS:/")
  apply(ange-ftp-hook-function file-attributes
"/username@IPADDRESS:/")
  tramp-ftp-file-name-handler(file-attributes
"/username@IPADDRESS:/")
  apply(tramp-ftp-file-name-handler file-attributes
"/username@IPADDRESS:/")
  tramp-file-name-handler(file-attributes
"/username@IPADDRESS:/")
  file-attributes("/username@IPADDRESS:/")
  find-file-noselect("/username@IPADDRESS:" nil nil t)
  find-file("/username@IPADDRESS:" t)
* call-interactively(find-file)