You don't have the diff program installed or your system can't find it.
This has nothing to do with ediff.
> Adrian,
> Thanks for your response. The output of the bug-report is below.
> Here is the value of exec-path:
>
> Value: ("C:\\Program Files\\XEmacs\\XEmacs-21.4.10\\i586-pc-win32\\"
> "D:\\PROGRAM DOWNLOADS\\ACTIVETCL\\bin\\" "D:\\Perl\\bin\\"
> "D:\\Perl\\bin\\" "C:\\WINNT\\system32\\" "C:\\WINNT\\"
> "C:\\WINNT\\System32\\Wbem\\" "C:\\PROGRA~1\\F-Secure\\Ssh\\Program\\"
> "C:\\Program Files\\SSH Communications Security\\SSH Secure Shell\\"
> "C:\\Program Files\\XEmacs\\xemacs-packages\\lib-src\\" "c:\\Program
> Files\\XEmacs\\XEmacs-21.4.10\\i586-pc-win32\\")
>
>
> To: xemacs-beta(a)xemacs.org
> Subject: Cannot find diff from ediff
> --text follows this line--
> This bug report will be sent to the XEmacs Development Team,
> not to your local site managers!!
> Please write in English, because the XEmacs maintainers do not have
> translators to read other languages for them.
>
>
> Please describe as succinctly as possible:
> - What happened.
> - What you thought should have happened.
> - Precisely what you were doing at the time.
>
> Please also include any C or lisp back-traces that you may have.
> ================================================================
> Dear Bug Team!
> Running XEmacs 21.4 in Windows 2000, when use the command ediff I get an
> error message:
> "Search for program: No such file or directory, diff"
> What do I need to do to get xemacs to find diff, which is present in
> cygwin.
>
> Thanks,
> David Zajic
> dmzajic(a)umiacs.umd.edu
>
>
>
> ================================================================
>
> System Info to help track down your bug:
> ---------------------------------------
>
> OS version:
>
>
>
> Microsoft Windows 2000 [Version 5.00.2195]
>
> OS: Windows_NT
>
>
>
> XEmacs 21.4.10 "Military Intelligence (Windows)" configured for
> `i586-pc-win32'.
>
>
>
> Building XEmacs in "f:\\xemacs\\xemacs-21.4-release\\nt".
>
> Using compiler "cl -nologo -W3 -O2 -G5 -ML".
>
> Installing XEmacs in "c:\\Program Files\\XEmacs\\XEmacs-21.4.10".
>
> Package path is "~\\.xemacs;;c:\\Program
> Files\\XEmacs\\site-packages;c:\\Program Files\\XEmacs\\xemacs-packages".
>
> Compiling in support for Microsoft Windows native GUI.
>
> Compiling in support for XPM images.
>
> Compiling in support for GIF images.
>
> Compiling in support for PNG images.
>
> Compiling in support for TIFF images.
>
> Compiling in support for JPEG images.
>
> Compiling in support for X-Face message headers.
>
> Compiling in support for toolbars.
>
> Compiling in support for dialogs.
>
> Compiling in support for widgets.
>
> Compiling in support for native sounds.
>
> Compiling in fast dired implementation.
>
> Using portable dumper.
>
>
>
> Load-Path Lisp Shadows:
> ----------------------
> nil
>
>
> Installed XEmacs Packages:
> -------------------------
>
> ((zenirc:version 1.13 :type regular)
> (xslt-process :version 1.11 :type regular)
> (xslide :version 1.03 :type regular)
> (xemacs-devel :version 1.48 :type single-file)
> (xemacs-base :version 1.71 :type regular)
> (w3 :version 1.26 :type regular)
> (vm :version 7.07 :type regular)
> (viper :version 1.35 :type regular)
> (view-process :version 1.12 :type regular)
> (vhdl :version 1.15 :type regular)
> (vc-cc :version 1.21 :type regular)
> (vc :version 1.33 :type regular)
> (tramp :version 1.1 :type regular)
> (tpu :version 1.12 :type regular)
> (tooltalk :version 1.13 :type regular)
> (tm :version 1.34 :type regular)
> (time :version 1.12 :type regular)
> (textools :version 1.13 :type regular)
> (text-modes :version 1.55 :type single-file)
> (texinfo :version 1.21 :type regular)
> (supercite :version 1.19 :type regular)
> (strokes :version 1.08 :type regular)
> (speedbar :version 1.24 :type regular)
> (sounds-wav :version 1.1 :type regular)
> (sounds-au :version 1.1 :type regular)
> (sml-mode :version 0.05 :type regular)
> (slider :version 1.13 :type regular)
> (sieve :version 1.1 :type regular)
> (sh-script :version 1.16 :type regular)
> (sgml :version 1.08 :type regular)
> (semantic :version 1.14 :type regular)
> (scheme :version 1.12 :type regular)
> (sasl :version 1.12 :type regular)
> (ruby-modes :version 1.0 :type single-file)
> (rmail :version 1.13 :type regular)
> (reftex :version 1.28 :type regular)
> (python-modes :version 1.01 :type single-file)
> (psgml-dtds :version 1.02 :type regular)
> (psgml :version 1.35 :type regular)
> (ps-print :version 1.08 :type regular)
> (prog-modes
>:version
> 1
> .67
>:type
> single-file)
> (pgg :version 1.01 :type regular)
> (perl-modes :version 1.02 :type single-file)
> (pcomplete :version 1.02 :type regular)
> (pcl-cvs :version 1.64 :type regular)
> (pc :version 1.25 :type single-file)
> (os-utils :version 1.29 :type single-file)
> (ocaml :version 0.03 :type regular)
> (net-utils :version 1.28 :type single-file)
> (mmm-mode :version 1.0 :type regular)
> (misc-games :version 1.15 :type single-file)
> (mine :version 1.14 :type regular)
> (mh-e :version 1.16 :type regular)
> (mew :version 1.17 :type regular)
> (mailcrypt :version 2.12 :type regular)
> (mail-lib :version 1.54 :type regular)
> (liece :version 1.1 :type regular)
> (jde :version 1.38 :type regular)
> (ispell :version 1.24 :type regular)
> (ilisp :version 1.28 :type regular)
> (igrep :version 1.1 :type regular)
> (idlwave :version 1.27 :type regular)
> (ibuffer :version 1.08 :type regular)
> (hm--html-menus :version 1.18 :type regular)
> (haskell-mode :version 1.03 :type regular)
> (gnus :version 1.64 :type regular)
> (gnats :version 1.15 :type regular)
> (games :version 1.13 :type regular)
> (fsf-compat :version 1.11 :type single-file)
> (frame-icon :version 1.09 :type regular)
> (fortran-modes :version 1.01 :type single-file)
> (forms :version 1.14 :type regular)
> (footnote :version 1.15 :type regular)
> (eudc :version 1.36 :type regular)
> (eterm :version 1.13 :type regular)
> (ess :version 1.02 :type regular)
> (eshell :version 1.03 :type regular)
> (emerge :version 1.09 :type regular)
> (elib :version 1.1 :type single-file)
> (eieio :version 1.03 :type regular)
> (efs :version 1.29 :type regular)
> (edt :version 1.12 :type regular)
> (edit-utils :version 1.95 :type single-file)
> (ediff :version 1.44 :type regular)
> (edebug :version 1.14 :type regular)
> (ecrypto :version 0.12 :type regular)
> (docbookide :version 0.05 :type regular)
> (dired :version 1.12 :type regular)
> (dictionary :version 1.11 :type regular)
> (debug :version 1.16 :type regular)
> (crisp :version 1.12 :type regular)
> (cookie :version 1.14 :type regular)
> (clearcase :version 1.04 :type regular)
> (cc-mode :version 1.31 :type regular)
> (calendar :version 1.19 :type regular)
> (calc :version 1.23 :type regular)
> (c-support :version 1.16 :type single-file)
> (build :version 1.07 :type regular)
> (bbdb :version 1.21 :type regular)
> (auctex :version 1.32 :type regular)
> (apel :version 1.25 :type regular)
> (ada :version 1.11 :type regular)
> (Sun :version 1.13 :type regular))
>
>
> Features:
> --------
>
> (mail-abbrevs xemacsbug shadow sendmail rfc822 env cus-face
> zenirc-autoloads xslt-process-autoloads xslide-autoloads
> xemacs-devel-autoloads xemacs-base-autoloads w3-autoloads vm-autoloads
> viper-autoloads view-process-autoloads vhdl-autoloads vc-cc-autoloads
> vc-autoloads tramp-autoloads tpu-autoloads tooltalk-autoloads
> tm-autoloads time-autoloads textools-autoloads text-modes-autoloads
> texinfo-autoloads supercite-autoloads strokes-autoloads
> speedbar-autoloads sounds-wav-autoloads sounds-au-autoloads
> sml-mode-autoloads slider-autoloads sieve-autoloads
> sh-script-autoloads sgml-autoloads semantic-autoloads scheme-autoloads
> sasl-autoloads ruby-modes-autoloads rmail-autoloads reftex-autoloads
> python-modes-autoloads psgml-dtds-autoloads psgml-autoloads
> ps-print-autoloads prog-modes-autoloads pgg-autoloads
> perl-modes-autoloads pcomplete-autoloads pcl-cvs-autoloads
> pc-autoloads os-utils-autoloads ocaml-autoloads net-utils-autoloads
> mmm-mode-autoloads misc-games-autoloads mine-autoloads mh-e-autoloads
> mew-autoloads mailcrypt-autoloads mail-lib-autoloads liece-autoloads
> jde-autoloads ispell-autoloads ilisp-autoloads igrep-autoloads
> idlwave-autoloads ibuffer-autoloads hm--html-menus-autoloads
> haskell-mode-autoloads gnus-autoloads gnats-autoloads games-autoloads
> fsf-compat-autoloads frame-icon-autoloads fortran-modes-autoloads
> forms-autoloads footnote-autoloads eudc-autoloads eterm-autoloads
> ess-autoloads eshell-autoloads emerge-autoloads elib-autoloads
> eieio-autoloads efs-autoloads edt-autoloads edit-utils-autoloads
> ediff-autoloads edebug-autoloads ecrypto-autoloads
> docbookide-autoloads dired-autoloads dictionary-autoloads
> debug-autoloads crisp-autoloads cookie-autoloads clearcase-autoloads
> cc-mode-autoloads calendar-autoloads calc-autoloads
> c-support-autoloads build-autoloads bbdb-autoloads auctex-autoloads
> apel-autoloads ada-autoloads Sun-autoloads lisp-autoloads loadhist
> auto-show fontl-hooks code-cmds gutter-items menubar-items x-menubar
> dragdrop mode-motion mouse itimer auto-save lisp-mode easymenu
> iso8859-1 page buff-menu lib-complete help-nomule cus-file derived
> frame text-props obsolete cus-start custom widget cl-extra mini-cl cl
> cl-19 packages backquote very-early-lisp file-coding
> mswindows-scrollbars mswindows toolbar native-sound scrollbar
> network-streams subprocesses menu-accelerator-support menubar md5
> xemacs gutter tiff png gif jpeg xface xpm xbm lisp-float-type
> windows-nt dragdrop-api dialog devices window-system base64)
>
>
> Recent keystrokes:
> -----------------
>
> misc-user
>
>
> Recent messages (most recent first):
> -----------------------------------
>
> Loading xemacsbug...done
> Loading xemacsbug...
> Loading env...done
> Loading env...
> Loading cus-face...done
> Loading cus-face...
>
>
>
>
>
>