gnuclient.emacs: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/gnuclient.emacs - from package: gnuserv

You may install the required package with command apt-get install {package}
Error in other languages:
gnuclient.emacs: bevel nie gevind nie
gnuclient.emacs: comandă negăsită
gnuclient.emacs: comando não encontrado
gnuclient.emacs: commande introuvable
gnuclient.emacs: command not found
gnuclient.emacs: käsku ei ole
gnuclient.emacs: không tìm thấy lệnh
gnuclient.emacs: komanda nerasta
gnuclient.emacs: Kommando nicht gefunden.
gnuclient.emacs: kommandot finns inte
gnuclient.emacs: komut yok
gnuclient.emacs: nie znaleziono polecenia
gnuclient.emacs: níor aimsíodh an t-ordú
gnuclient.emacs: no se encontró la orden
gnuclient.emacs: no s'ha trobat l'ordre
gnuclient.emacs: opdracht niet gevonden
gnuclient.emacs: parancs nem található
gnuclient.emacs: perintah tidak ditemukan
gnuclient.emacs: príkaz nenájdený
gnuclient.emacs: příkaz nenalezen
gnuclient.emacs: команда не найдена
gnuclient.emacs: командата не е открита
gnuclient.emacs: 命令找不到
gnuclient.emacs: コマンドが見つかりません