gopher: command not found

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/gopher - from package: gopher

You may install the required package with command apt-get install {package}

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